14 - Human Development

proper nutrition

"Now you're eating for two," people sometimes say to pregnant women. This is because a pregnant woman needs to eat more calories to support the growth of her own body and the developing embryo or fetus. During pregnancy, a woman needs to consume about 300 more calories than usual. The best way to obtain these extra calories is to eat a well-balanced diet rich in the key nutrients listed in interactive at right. One vitamin that is especially important during pregnancy is folic acid, or folate. Folic acid is essential for proper development of an embryo's neural tube, which later develops into the spinal cord and brain. The neural tube forms early in an embryo's development, often before a woman knows she is pregnant. Therefore, a woman should not wait until she knows she is pregnant to get enough folic acid. Doctors recommend that all women of childbearing age consume at least 0.4 mg (400 micrograms) of folic acid every day.

idk

1. Fertilization Only a few hundred sperm of the hundreds of millions that enter the vagina usually make it to the egg, and only one can fertilize it. Within seconds of fertilization, the surface of the egg changes so that no more sperm can enter the egg. In the first week after fertilization, the fertilized egg undergoes many cell divisions and travels to the uterus. 2. The Zygote The united egg and sperm is called a zygote (ZY goht) Within 36 hours, while the zygote is still traveling through the fallopian tube, it begins to divide. 3. Cell Division The original cell divides to make two cells. From the two-cell stage until about nine weeks after fertilization, the growing structure is called an embryo (EM bree oh). The two-celled embryo divides into four cells, and so on. 4. The Blastocyst About five days after fertilization, the embryo reaches the uterus, where it floats free for a few days. By this time, it is made up of about 50 to 100 cells. The structure, called a blastocyst, is no longer a solid mass of cells, but a sphere of cells surrounding a hollow center. 5. Implantation Once the blastocyst forms, it begins to attach itself to the wall of the uterus. The process of attachment is called implantation.

low birthweight

A newborn that weighs less than 5.5 pounds at birth is considered to have low birthweight. Some low-birthweight babies are also premature. Others are full-term, but just didn't grow enough before birth. Premature and low-birthweight babies face an increased risk of health problems as newborns, chronic lifelong health problems, and even death. Not all cases are preventable—however, the number of premature and low-birthweight babies could dramatically decrease if more women adopted healthy habits during pregnancy. For example, a woman reduces her risk of having a baby with low birthweight by about 40 percent by not smoking during pregnancy.

the three trimeters

A pregnancy is divided into three periods of time—trimesters—each of which is approximately three months long. first - record medical history and weight - note conditions that could affect the pregnancy - prescribe prenatal vitamins as needed second - monitor heartbeat of fetus - measure growth of uterus - monitor for complications using ultrasound and other tools third - check position and size of fetus - check for warning signs of premature, or early, birth - continue to monitor for complications - discuss birth process

umbilical cord

About 25 days after fertilization, a ropelike structure called the umbilical cord (um BIL ih kul) develops between the embryo and the placenta. The umbilical cord is the embryo's lifeline. Blood vessels in the umbilical cord carry nutrients and oxygen from the placenta to the embryo and wastes from the embryo to the placenta.

growing pains

Adjusting to changes in your body proportions can be difficult at times. Rapid lengthening of the bones in your arms and legs can cause aches and cramps. It can also make you feel awkward. You may feel as if you are tripping over your own feet, or you may find that you are no longer comfortable in your favorite chair. If you challenge your growing body with a variety of physical activities, you will adjust more rapidly to your new size and shape. Physical activity will also help to develop your muscles and your coordination. As unlikely as it may seem, your feelings of discomfort and awkwardness will soon disappear.

thinking about your future

Adolescence is also a time to begin looking toward the future. During these years, you make many decisions that can affect your future career opportunities. You now know that you have to plan and work for what you want—these things do not just happen on their own. There is plenty of time to figure out what you want to do, or to change your mind. However, making responsible decisions now can help keep your options open.

healthy aging

After about the age of 30, adults begin to experience changes associated with the aging process. Aging is a normal biological process that you cannot avoid. However, there are many things you can do over your lifetime to slow the effects of aging. People tend to reduce or delay the physical signs of aging when they establish healthy behaviors during their youth.

development of the uterus

After implantation, development continues in the uterus. While the embryo grows, several other structures also develop. These structures—the amniotic sac, placenta, and umbilical cord—protect and nourish the developing embryo, and later the fetus. The embryo is surrounded by several protective structures. Use the interactive figure to learn more about them.

postpartum period

After the birth, a period of adjustment for the parents and their newborn begins. During the first six weeks, called the postpartum period, many changes take place. Immediately after the birth, the newborn's lungs begin to function for the first time. The circulatory system and heart undergo changes that send more blood to the lungs, where the baby now gets oxygen from the air. The nervous system reacts to new sensations: light, air against the skin, a parent's touch, hunger, and pain. While its organs adjust to life outside the uterus, the newborn is learning to get what it needs by forming a strong bond with its mother and father. For the mother, changing hormone levels signal the breasts to produce milk and cause the uterus to gradually shrink back to its normal size. Hormonal changes and fatigue may cause the mother to feel overwhelmed, or even very sad, during the postpartum period. Usually, these "baby blues" pass within a few days. If, however, the sadness lasts longer or causes the mother to withdraw from the baby and other people, she should seek prompt medical attention. She may need to be treated for a serious condition called postpartum depression.

complication at birth

Although the birth process usually proceeds smoothly, problems can sometimes occur. Some complications result in a surgical delivery or premature birth. Low birthweight and the birth of more than one baby also may cause complications. In addition, very rarely, a pregnancy may end with a stillbirth. A stillbirth occurs when a fetus dies and is expelled from the body after the twentieth week of pregnancy.

staying healthy during pregnancy

Amanda starts her day with a bowl of oatmeal. Later, she and her husband go out for a brisk walk. At night, she skips a party where people will be smoking. Amanda and her husband are thinking about having a baby. Even before she becomes pregnant, Amanda started taking extra care to have a healthy pregnancy. Getting proper nutrition and exercise and avoiding drugs and environmental hazards are especially important both before and throughout pregnancy.

marraige

Approximately 90 percent of all Americans marry at some time during their lives. Therefore, it is highly likely that you will marry someday. If you do choose to marry, it will probably be one of the most important decisions you will make. It will affect you, your spouse, your family, your friends, and future generations.

height and muscle mas

Around the same time that puberty starts, the pituitary gland also increases its production of growth hormone. Growth hormone is a chemical messenger that activates growth. Growth occurs in spurts. Some months little growth hormone is produced, and you do not seem to grow at all. Other months there is a surge of growth hormone, and you seem to grow overnight. If you were to look at a group of young adolescents, you would notice that, for the most part, the girls are taller than the boys. Girls tend to begin their growth spurt earlier than boys. If you looked at the same adolescents at the end of high school, however, the boys would be taller than the girls, for the most part. Boys start their growth spurt later, but they grow for a longer period of time—eventually becoming taller than girls, on average.

avoiding alcohol and other drugs

As soon as she plans to become pregnant, a woman should abstain from all alcohol, tobacco, and any other drugs not prescribed or approved by her doctor. These substances, even in small amounts, can harm or kill the developing baby, decrease the newborn's chance to live, or cause lifelong problems. For example, women who drink alcohol during pregnancy risk having a baby with fetal alcohol syndrome, which can cause mental retardation, minor to severe heart defects, and delayed growth. Some drugs that are typically safe outside of pregnancy can cause harm to a fetus. A pregnant woman should talk to her doctor before using any prescription drugs or over-the-counter drugs, including pain medications, creams and lotions, and vitamins. Likewise, a woman should get her doctor's approval before drinking herbal teas or using other herbs.

the birth process

As the baby's due date approaches, the mother and father prepare. Most couples choose to have their baby in a hospital, where obstetricians, specially trained nurses, and medical equipment are available should something go wrong. If the pregnancy has gone well and the mother is in good health, a couple may choose to have the baby at home or at a home-like setting with the help of a certified nurse-midwife. A certified nurse-midwife is a nurse who is trained to deliver babies. Near the end of the ninth month of pregnancy, the head of the fetus moves lower in the uterus. The birth process begins when the muscular walls of the uterus begin a series of contractions that will push the fetus out of the mother. Birth takes place in three stages—labor, delivery of the baby, and delivery of the afterbirth.

responsibility to community

As you continue through your teen years, you will begin to see yourself as an important part of your larger community. You may also recognize that your actions directly affect community life. For example, you probably appreciate clean streets and parks, and you like knowing that cars will stop at red lights when you are crossing the street. Now you are mature enough to see that these benefits depend on you and people like you. Littering, vandalism, or reckless driving endangers the quality of life in a community. Some of these irresponsible behaviors are also dangerous, and many of them are against the law. During your teen years, you become responsible for knowing the laws of your community and for obeying them. You are expected to think about the effect that your actions will have, not only on yourself and your friends but also on the community as a whole. Acting responsibly is a way of showing your new maturity. You may even want to go further in helping to improve your community. Participating in cleanup or fund-raising activities or giving aid directly to less fortunate community members can be satisfying. During adolescence, many teens become more interested in public issues, and they find that their actions can have a noticeable positive effect on their community.

young adulthood

At what point do you become an adult? On a certain birthday? When you are financially independent? When you marry? When you have physically matured? From a legal standpoint, Americans are considered to be adults at the age of 18 for some activities and at the age of 21 for others. From a physical and emotional standpoint, however, it is difficult to say when adulthood begins. During the next few years, you will begin the transition from adolescence to adulthood. You will change physically and emotionally during the transition from adolescence into young adulthood. In fact, changes continue throughout your life as an adult.

prenatal care

Besides taking care of herself at home, a woman also needs to plan for prenatal care, or medical care during her pregnancy. Her doctor visits should be under the supervision of an obstetrician, a doctor specialized in pregnancy and childbirth. The chances of having a healthy baby greatly increase if the mother visits her doctor or clinic for regular checkups throughout pregnancy.

grieving afterdeath

Dealing with your grief after a loved one dies is not easy. It may be even more difficult if the death is sudden. After the death of a loved one, it is important not to deny your feelings. However, don't become so overwhelmed with emotion that you forget to take care of yourself. Try to talk about your loss. Discuss your feelings with family and friends or write them in a journal. Talk about how you miss the person. Think of how you would like to remember the person. Continue your usual routine as much as possible. This will help you focus your mind on something other than the death. It will also help get you out of the house and see other people. Allow yourself some time to grieve. However, if your feelings of grief do not lessen after a time, seek help from an close adult or professional.

dying with dignity

Death is part of the normal cycle that all living things go through. No amount of fame, money, or love prevents death. As strange as it sounds, dying is a part of living. Still, it is never easy to face death, whether one's own or that of a loved one. However, understanding the process and learning some strategies for coping can help.

responsibility to family

Despite images in the media that show teenagers as angry, rude, and rebellious, most teenagers are happy, healthy people who value their families. Research shows that most families are able to work out the conflicts that normally arise as teenagers strive for more autonomy. Working out these conflicts involves some give and take on the part of both parents and teens. It helps to show respect for the feelings, tastes, and values of family members on minor issues, such as clothing styles. This sets the stage for increased independence on bigger issues, such as borrowing the family car. With increased independence at home come increased responsibilities. What are your responsibilities to your family? Helping Out You may now be responsible for more of the physical work needed to maintain your household. You may need to learn new skills, such as house painting, grocery shopping, or laundering. You may be responsible for taking care of a younger brother or sister after school. Perhaps you are contributing to the family finances with money you bring home from an after-school job. Giving Back You are responsible for becoming more of a "giver" in your family relationships. You are now mature enough to offer understanding and support to other family members. You can participate more fully in the emotional life of your family. For example, if your sister is studying for a test, you can offer encouraging words and help her study. Playing by the Rules Another responsibility is to follow your family guidelines about clothing, curfews, and other activities. This does not mean that your parents make all of the rules all of the time. You can help your parents establish guidelines that are right for you.

making everyday decisions

During adolescence you become responsible for taking care of yourself. It's up to you to eat nutritious meals, exercise, and visit the dentist. You are responsible for other decisions, too, such as what to wear. If you pay for some or all of your clothes and other personal items, you also become responsible for managing a budget.

reasoning skills

During adolescence, changes to your brain also help to expand your reasoning abilities—including the way you solve problems and make decisions. You are becoming increasingly able to see more than one side of a question and to think through the pros and cons of decisions you face. As you gain experience making wise choices in simple everyday dilemmas, you find it easier to make wise choices when more difficult situations arise.

search for meaning

During adolescence, it is not unusual to suddenly question whether your friends are really true friends and whether happiness and love are possible to attain. These questions signal that you have begun to search for meaning in life. This search is important because you are beginning to choose a way of life that is right for you. Some teens find answers to these questions by talking with parents or other trusted adults. Others explore these questions through their own experiences. For example, some teens volunteer in hospitals or food pantries. Such experiences often help them figure out what is important to them.

emotional changes

During adolescence, you may feel like you are on an emotional roller coaster—very happy one moment, and miserable the next. You are not alone in having these strong feelings—all teens experience them. For many teens, adolescence is a time for questioning. You may begin to question many things that you have simply accepted until now. You may start to question the actions and values of people around you, such as friends and family members. Most important, you may start to question yourself. During adolescence, individuals start to define meaning in their lives, a set of personal values, and a sense of self.

responsibility to friends

During adolescence, you may realize that your friends are more than just people with whom to have fun. Friends are people who really listen when you talk and who support you when you have a problem. You have similar responsibilities toward them. You should be willing to take time away from your activities to help out a friend, to be a good listener, and to offer comfort and encouragement when needed. You may also witness some friends engaging in destructive or dangerous behaviors. When you have a concern about a friend's health, safety, or well-being, you have a responsibility to try to help. Peer pressure—in spite of the way the term is often used—can be a positive force. You can use peer pressure to influence your friends in positive directions and to provide a network of support in times of stress or crisis.

growing embryo

During the first two months of development, the major body systems and organs start to form in the embryo. For example, a basic heart, major blood vessels, kidneys, and endocrine glands develop. By the end of eight weeks, the embryo is about an inch long and has recognizable external features such as eyes, ears, arms, and legs. The head is large in proportion to the body—it makes up nearly 50 percent of the length of the embryo.

3. delivery of afterbirth

Even though the baby is born, the birth process is not complete. The third stage involves contractions of the uterus that push out the placenta, also called the afterbirth. This stage typically takes about 15 to 30 minutes.

parenthood

For some people, young adulthood is not only a time for marriage but also a time to become parents. The relationship between parent and child is critical to the child's healthy development. Parents need to be able to commit a lifetime of love, guidance, and attention to their children. At least one part of making the decision to become parents is purely practical. A couple should review their budget to find out whether or not they can afford to provide food, clothing, and medical care for a child. They need to discuss who will care for the child if both spouses continue to work. They need to find out if their employers grant maternity or paternity leave, so that one of them can stay home for a few months and then return to the same job. They may also need to investigate the costs and availability of childcare.

diseases of older adulthood

For someone born in 1900, life expectancy was only about 47 years. In contrast, boys born today can expect to live about 75 years, and girls about 80 years. Living longer means that people can watch their grandchildren, or even their great-grandchildren, grow up. But living longer also increases the likelihood that a person will get a disease associated with the aging process. The most common diseases that strike older adults include heart disease, cancer, and lung disease. Other common diseases of older adulthood include: Arthritis This disease attacks the body's joints. It can make simple tasks, such as holding a pencil or climbing stairs, very painful. Arthritis can be managed with pain medication and physical activities that are gentle on the joints, such as exercising in water. Osteoporosis The bones of older people tend to break easily and heal slowly. This is due to osteoporosis, a condition caused by a loss of bone calcium. Medications can help slow calcium loss. In addition, railings installed along stairs and in bathtubs can help prevent falls that could fracture bones. Other common diseases of older adulthood include: Parkinson's disease This disease of the nervous and muscular systems causes the muscles to become stiff. A person experiences shaky movements and progressive loss of muscle function. Medications can slow the progression of this disease. Dementia About 10 percent of older adults suffer from dementia (dih MEN shuh), a disorder characterized by loss of mental abilities, abnormal behaviors, and personality changes. Dementia has several causes, some of which can be treated. Alzheimer's Disease Alzheimer's disease (AHLTS hy murz) causes brain cells to die, resulting in the gradual loss of mental and physical function. There is no cure, but some medications may slow the progression of the disease.

fetus

From the third month until birth, the developing human is called a fetus. During the third to sixth month, the fetus begins to move and kick, a sign that its skeleton and muscles are developing. As its nervous system matures, the sense organs begin to function. The fetus becomes sensitive to light and sound and alternates periods of activity with periods of sleep. From the seventh to the ninth month, the fetus continues to grow and develop. The size of the body increases so that it is more in proportion to the size of the head, and body fat accumulates. The eyelids open and close. By the end of the ninth month, the fetus is ready to be born.

search for values

Have you started to question the opinions and beliefs of others, especially those of your parents? This process helps you discover your values—those beliefs that are important to you. Although you may disagree with your parents at times, they can offer you guidance and serve as role models. Parents, teachers, and other adults can help you clarify your values. For the most part, many of the values that adolescents eventually come to accept are similar to those of their parents.

mental changes

Hormones control most of the outward physical changes of adolescence. But changes in the way you think and feel have more to do with changes occurring in your brain. In your first few years of life, millions of brain cells and the pathways connecting them formed. Then, when you were between 10 and 13 years old, a second dramatic wave of growth and development took place. In fact, your brain grew a bit too much! During the rest of your adolescence, your brain will be "pruned back." Only the brain cells and connections that you use will survive and flourish. Scientists are discovering how changes in the brain affect teenage development. Mental changes during adolescence include improved abstract thinking, reasoning skills, and impulse control.

helping others through their grief

How can you support your friends when they have lost a loved one? Be a good listener. Your grieving friend may want to sort through some emotions by talking to you. Write a sympathy note. Remember that your friend will be feeling his or her loss in a unique and personal way. Don't say things like "I know how you must feel," or "You'll get over it soon." Instead, say "I'm thinking of you," or "I'm here if you want to talk." Help with everyday errands. Offer to bring homework assignments home for your friend, bring the family a meal, or run other errands. If necessary, help your friend get counseling. If your friend doesn't seem to be making any progress after time, ask a trusted adult to help you get your friend in touch with a grief counselor.

your role in the family

How does your status as an adolescent affect your relationships with your family? In many families, the family unit and family rules are valued more highly than a teenager's autonomy, or independence. This may lead to friction between generations. Parents may expect their teens to stick to the older ways. At the same time, teens may be pulled in other directions by their peers.

early bloomers and late bloomers

If you are like most adolescents, you have probably compared your own physical development to that of your peers. Some of your classmates may already look like adults, while others may be just starting to show signs of puberty. You can see in the figure that the age range for the "normal" onset of puberty is wide. Some people start puberty before middle school, some start puberty toward the end of high school, and others start somewhere in between. Adolescents who develop at an early age, before most other adolescents, are sometimes called early bloomers. Those who develop at a late age, after most other adolescents, are called late bloomers. Although they may not think so, most early bloomers and late bloomers are developing at a normal rate. What accounts for the wide range of ages at which puberty and the growth spurt begin? The ages at which people mature sexually and grow to their adult height are determined in large part by heredity. You are probably maturing at about the same age and speed as your parents did. Another factor that influences your unique timetable of development is your overall state of health.

physical maturity

If you look up the term adult in the dictionary, you might find this definition: "fully developed and mature." Most people reach physical maturity, the state of being full-grown in the physical sense, by their late teens or early twenties. By this time, all of your body systems are fully developed, and you are as tall as you will ever be. Your physical abilities—your strength and speed, as well as your breathing and heart efficiencies—will reach their peak during young adulthood.

changes in your body

If you were to compare a recent photograph of yourself to one taken three years ago, you would notice many changes. From about the ages of 12 to 19, you gradually change from a child into an adult. This period of gradual change is called adolescence. During adolescence, a person undergoes many physical, mental, and emotional changes. As photographs reveal, adolescence is a period of rapid physical growth. However, photos show only some of the physical changes taking place. Important physical changes are also occurring inside the body during this time. During adolescence, the reproductive system matures, adult features appear, and height and muscle mass increase.

emotional and social changes

Maintaining emotional and social health during adulthood is also important for healthy aging. For many people, adulthood is a time of contribution to their family and community. For example, adults in midlife may help take care of their grandchildren or their aging parents, or may serve as volunteers in their community. They must find a healthy balance between meeting their own needs and helping others. You may have heard the phrase "midlife crisis" used to describe the emotions that some adults experience. Many adults do undergo a period of self-evaluation—comparing the dreams they had in young adulthood with their actual accomplishments. But despite the phrase, this period of self-evaluation does not usually have a bad outcome. A midlife crisis can lead to positive change—a different career, a return to school, or travel. Older adults may begin to reflect on their lives. Accepting the good and the bad in their past without regrets helps them enjoy the time they have left. Older adults can best maintain their emotional health if they continue to stay psychologically connected to others. It also helps if they stay committed to something that gives meaning to their lives, such as family, friends, religion, or community activities.

your career

One major concern of young adults is finding a career in which they feel productive and satisfied. During adolescence, you need to think, plan, and prepare for your life's work. During young adulthood, you make decisions and take action towards your career goals. You need to know what skills, education, and training are necessary to achieve your goal. You also should consider the income you will need to earn to be self-supporting. If you get married and have children, you will have to juggle your work responsibilities with the needs of your family.

beginning of the life cycle

Parenthood has many joys and satisfactions, but it is also stressful and involves a lot of hard work. The responsibilities of parenthood go far beyond those of most other occupations. Babies are demanding and totally helpless. Along with the loving feelings, smiles, and cuddles, new parents face sleepless nights, worries about illness, and the loss of many freedoms they used to enjoy. Parents must also be prepared to give their child love and guidance throughout his or her life, not just as a baby. Once a couple has decided to start a family, they may try to conceive, or get pregnant. In a fertile woman's body, about once a month an egg enters one of the fallopian tubes and begins its journey to the uterus. During sexual intercourse, sperm from the man are deposited into the vagina. Some of these sperm swim through the uterus to the fallopian tubes. If the egg is on its way to the uterus, a sperm may fertilize it. This moment of fertilization is also called conception.

why people marry

People marry for a variety of reasons. Some people marry because they desire another person's love and companionship. Others marry for financial, social, or cultural reasons. Some couples marry in order to start a family of their own. You need to know yourself fairly well before you select a marriage partner. You need to know what your goals are and how you are going to achieve them. You need to know what is important to you. When it comes time to marry, people usually select marriage partners who have similar interests, values, level of education, and social background to themselves. People who are quite different from each other can also have successful marriages, but they may have to work harder to overcome their differences.

monitoring tools

Prenatal care gives a pregnant woman access to the latest medical tests and technologies. Ultrasound Did you know that your first pictures may have been taken months before you were born? High-frequency sound waves, or ultrasound, are used in most pregnancies to create an image of the developing fetus. Ultrasound may be used at any point during pregnancy, although it is typically used in the sixteenth to twentieth week. Using ultrasound, a doctor can tell the age of the fetus, whether it is a boy or girl, and if the heart, muscles, and bones are developing normally. Ultrasound may also detect the presence of more than one fetus or confirm the position of the fetus in the uterus. Chorionic Villus Sampling Around the eighth week of pregnancy, some women will undergo a test called chorionic villus sampling, or CVS. To perform the test, the doctor removes and tests a small piece of the developing placenta. CVS can detect inherited disorders in the embryo such as hemophilia or extra chromosomes. The test is only done when risk factors are present, such as a family history of genetic disorders or when the mother is over the age of 35. An older mother has an increased risk of having a baby with Down syndrome or other chromosomal abnormalities. Amniocentesis Another test that may be done around the fourteenth to sixteenth week of pregnancy is amniocentesis (am nee oh sen TEE sis). The procedure involves inserting a needle into the woman's abdomen and uterus to remove a small amount of amniotic fluid surrounding the fetus. The doctor then tests fetal cells naturally found in this fluid for abnormalities. Like CVS, amniocentesis is only performed when the fetus is at higher risk for a genetic disorder. CVS and amniocentesis are not routine tests because they slightly increase the risk of miscarriage, or death of the fetus.

complications

Problems can occur anytime during pregnancy. For some of these complications, timely treatment can reduce negative consequences or even save the life of the woman or fetus. Ectopic pregnancy In the very rare case of an ectopic pregnancy, the blastocyst implants in the fallopian tube or elsewhere in the abdomen, instead of in the uterus. It cannot develop normally and may put the mother's life at risk. Surgery is necessary to remove the embryo and repair the damaged fallopian tube. Miscarriage The death of an embryo or fetus in the first 20 weeks of pregnancy is called a miscarriage. Over 20 percent of pregnancies end in miscarriage. Miscarriage almost always occurs during the first trimester, sometimes before a woman knows she is pregnant. Miscarriage is usually caused by a serious genetic defect, but is sometimes due to illness or a drug the mother has taken. In other cases, there is no apparent reason for a miscarriage. Preeclampsia Also called toxemia, preeclampsia (pree ih KLAMP see uh) is characterized by high blood pressure, swelling of the wrists and ankles, and high levels of protein in the urine. Its onset is usually in the second or third trimester. Preeclampsia prevents the fetus from getting enough oxygen. This serious condition is treated with bed rest or medication. Gestational Diabetes Diabetes that develops in pregnant women is called gestational diabetes, and is marked by high blood sugar levels. Like preeclampsia, it usually develops later in pregnancy. If left untreated, excess blood sugar that passes through the placenta to the fetus may cause the fetus to grow too big. This increases the risk of a difficult birth, as well as breathing problems and obesity in the newborn.

reproductive system

Puberty usually begins before you reach adolescence and ends during mid-adolescence. Puberty is the period of sexual development when a person becomes sexually mature and able to reproduce. You may have heard the term puberty used in many different ways. Some people use the term to refer to all of the changes of adolescence. However, the term refers specifically to the changes that happen to your reproductive system. Sex hormones control the changes that occur during puberty. At some point between the ages of 9 and 16, the pituitary gland in the brain signals a girl's ovaries or a boy's testes to begin producing sex hormones. The ovaries produce estrogen and progesterone while the testes produce testosterone. The release of sex hormones causes girls to begin to ovulate and menstruate, and boys to begin to produce sperm. Ovulation in girls and sperm production in boys signal reproductive maturity, or the ability to produce children. Early in puberty, the body does not produce sex hormones consistently. In girls, this affects the regularity of the menstrual cycle. Many girls begin to ovulate before their menstrual cycles become regular. In fact, in some girls, menstrual cycles do not become regular for many years. As the glands mature, hormone production becomes more regular.

exercise

Regular physical activity is also important for a healthy pregnancy. A fit woman will better meet the extra energy demands of carrying the fetus. She also reduces her risk for diabetes and other health problems during pregnancy. A woman should get her doctor's approval for her exercise program. Some forms of exercise should be avoided—for example, horseback riding, where there is a high risk of falling.

avoiding environmental hazards

Some common substances found in the environment, including many chemicals and disease-causing organisms, can seriously harm a fetus. Pregnant women should take care to avoid exposure to these substances. X-rays The radiation from X-rays can harm a developing embryo or fetus. This is why doctors and dentists ask women if they could possibly be pregnant before taking an X-ray. Lead The main source of exposure to lead is from lead-based paint present in older homes. If a pregnant woman lives in a home built before 1978, she should contact her state health department for information on getting her home tested for lead. Mercury Most exposure to this dangerous metal comes from eating contaminated fish. Pregnant women should eat commercially caught fish only once a week, and should not eat swordfish or shark. Cat litter Cat feces can contain a parasite that is especially dangerous to a developing fetus. Pregnant women should avoid contacting soiled cat litter or garden soil.

search for self

Some of the most difficult questions that adolescents ask concern themselves and their place in the world. These questions are signs of a search for who you are—your identity. This search for identity may take many forms. You might discuss the question of identity with others, or you might compare yourself to people you admire. Sometimes you may try out different personalities by experimenting with new hairstyles, different clothing, and even new behaviors. Exploring your racial and ethnic traditions may be another important part of your search for identity. If you are like many adolescents, your self-esteem may not be as high today as it was a few years ago. Right now your feelings about yourself are strongly influenced by the opinions of others, particularly your peers. You may worry whether your peers approve of your clothing, your looks, your personality, and your interests. It is normal to have these worries. In time, these feelings will lessen. It is not always easy to maintain a clear and consistent picture of yourself, or to feel positive about who you are. Try listing your accomplishments and writing about your talents in a journal. When the question "Who am I?" comes up, you can find some good answers by looking in your journal.

impulse control

Some teenagers find that their impulses, or tendencies to act rapidly based on emotional reactions, are sometimes clouding their decision-making abilities. Maybe a friend dares them to do something dangerous, and before they consider the consequences, they go ahead and do it. The emotional region of an adolescent's brain is more active than the same region in an adult's brain. Scientists hypothesize that greater activity in the amygdala may be one reason why it is harder for teens to ignore impulses. You may not like the consequences of acting on your impulses. Removing yourself from an intense situation and taking some time to think things through can help you stay in control. As you mature, your impulse control will improve.

premature birth

Sometimes a baby is born before it has developed fully. Delivery of a live baby before the 37th week of pregnancy is called premature birth. The earlier the birth, the more problems the baby tends to have. The lungs of a premature baby are usually not fully developed, and in some cases, the baby cannot breathe by itself. The baby may also have additional problems if other organs aren't fully developed. A premature baby may receive care in an incubator, a chamber designed to protect the baby until it has developed more.

surgical delivery

Sometimes delivery through the cervix and vagina is not possible because of the position of the fetus in the uterus or the narrowness of the mother's hips. Other times, illness or other conditions may make labor and vaginal delivery dangerous for the mother or the fetus. In these circumstances, the obstetrician will perform a cesarean section. A cesarean section (suh ZEHRbee un) is a surgical method of birth. The operation takes about one hour to complete, and the mother may be awake or asleep during the procedure. First the doctor makes an incision in the lower abdomen into the uterus, then he or she removes the baby and placenta. About 25 percent of all babies born in the United States are delivered by cesarean section.

fraternal twins

Sometimes two eggs are released from the ovary and are fertilized by two sperm. When this happens, fraternal twins develop. Fraternal twins are no more alike than any other siblings, and they may or may not be the same sex.

amntiotic sac

Soon after implantation, a fluid-filled bag of thin tissue called the amniotic sac (am nee AHT ik) develops around the embryo. The sac continues to grow in size as the embryo grows. Inside the sac, the embryo floats in amniotic fluid.

2. delivery of baby

Stage two involves the actual birth, or delivery, of the baby. This stage can take from half an hour to more than two hours. Contractions of the uterus continue, and the baby is pushed out, usually head first, through the cervix and vagina. Once the baby is out, the doctor clamps and cuts the umbilical cord. There are no nerve endings in the cord, so this does not hurt the baby or the mother. The baby's nose and mouth are suctioned to remove mucus and make breathing easier. Eye drops are put in the baby's eyes to prevent infection, and an injection of vitamin K is given to prevent excessive bleeding from the cut umbilical cord. The doctor may also prick the baby's heel for a blood sample, which will be tested for abnormal protein levels. Abnormal test results may indicate a genetic disorder.

emotional support

Staying silent or absent doesn't help either the dying person or your grieving process. Staying actively involved in a dying loved one's life will help both you and the dying person cope. Visit the person as often as you can. Make dying a time for loving and sharing, not loneliness and despair. Listen to what the dying person has to say. Let the dying person direct the conversation. Let him or her talk about the past. Others may want to talk about what is happening to them. Try not to be shy about discussing death. If death frightens you, think of the dying person as someone who is about to set out on a long journey. Try to share your feelings of loss before a loved one goes. Talk about your plans and hopes. Even though the person will not be there to share the future with you, it will cheer the person to think about things other than the present.

coping skills

Suppose your grandparent, parent, or friend is dying. Like most people, you may find it very uncomfortable to deal with death and dying. Some people try to cover up their grief by false cheer—they pretend that everything is fine and that they are happy. Others may refuse to talk about their grief. Some keep away from the dying person. These are generally not healthy strategies. What should you do if a person close to you is dying?

placenta

The attachment holding the embryo to the wall of the uterus develops into a structure called the placenta. Within the placenta, oxygen and nutrients move from the mother's blood into tiny blood vessels that lead to the embryo. Dangerous substances can pass from mother to embryo, too, including alcohol, drugs, the chemicals in tobacco smoke, and some microscopic organisms that cause disease. Any of these substances can seriously harm the developing embryo.

multiple births

The delivery of more than one baby—for example, twins, triplets, or quadruplets—is called a multiple birth. These births carry greater risk to the mother and babies, and are closely monitored by doctors. Delivery by cesarean section is more likely for a multiple birth than for a single birth. What causes more than one fetus to develop?

care for the dying

The process of dying has changed in the last few decades. In the past, most people died in their homes, surrounded by family and friends. The medical advances that have lengthened the average life span have also given doctors the ability to prolong the life of a dying person. Today, a person is more likely to die in a nursing home or hospital than at home. Some people who are dying choose to be cared for in a hospice (HAHS pis). A hospice is a facility or program that provides physical, emotional, and spiritual care for dying people and support for their families. Some hospice programs have their own facilities where hospice workers can give dying patients round-the-clock care. Other hospice workers visit the dying person at home or in the hospital. Hospice workers help patients and their families to accept death and to enjoy whatever time is left. To make hospice affordable, most of the workers, except for medical personnel, are trained volunteers.

appearance

The sex hormones also cause the development of secondary sex characteristics, which are physical changes that develop during puberty, but are not directly involved in reproduction. Secondary sex characteristics are different for men and women. The physical changes at puberty can be overwhelming at times. Some adolescents have difficulty adjusting to their changing body shape, or may be embarrassed or confused about the sexual changes occurring to their bodies. Having someone to talk to, especially a trusted adult, can help adolescents understand and accept their feelings.

stages of labor

The three stages of birth include labor, delivery of the baby, and delivery of the afterbirth.

1. labor

The work performed by the mother's body to push the fetus out is called labor. Labor for a first child may last from about 2 to 24 hours or longer. During this stage, strong contractions of the muscles of the uterus cause the cervix to increase in width, or dilate. Each contraction typically lasts from 30 to 90 seconds. At first, the contractions may be minutes apart, but by the end of labor, they are usually only a few seconds apart. Near the end of this first stage, the amniotic sac breaks, and the cervix becomes softer and wide enough for the fetus to pass through.

stresses in marriage

Throughout marriage, a couple must be willing to make adjustments to meet each other's needs. The changes in attitudes and expectations that these adjustments require can produce stress. One difficult adjustment in marriage can be determining the responsibilities that each spouse will have. Some couples decide early in their marriage how each person will contribute financially and who will do certain household tasks. Who will do the cooking? Who will pay the bills? By compromising and accepting tasks that fit their abilities and schedules, a couple usually can develop a comfortable give-and-take relationship. When changes occur, such as the birth of a child or a new job, the couple may need to redefine their responsibilities.

triplets or more

Triplets, quadruplets, and other multiple births are less common than twins. The number of births to three or more babies has increased dramatically in the last 25 years.

identical twins

Twins that develop from a single fertilized egg, or zygote, are called identical twins. Early in development, the embryo divides into two identical embryos. Because they develop from identical embryos, identical twins have the same inherited traits and are the same sex.

emotional maturity

Unlike physical maturity, adults reach emotional maturity, or full development in the emotional sense, over their lifetime. There are three major factors that contribute to emotional maturity—developing close relationships with others, giving back to society, and learning to accept yourself for who you are. In young adulthood, an important emotional milestone is the establishment of close relationships with individuals outside your family. As an adult, you are more likely to form long-lasting friendships than you are forming now as an adolescent. Why? You will have a better sense of who you are, and be better able to choose friends with interests and values similar to your own. Having a clear idea of who you are and trusting others will also give you the foundation for emotional intimacy. Emotional intimacy is the openness, sharing, affection, and trust that can develop in a close relationship.

physical changes

What physical changes occur as people age? Adults may notice that their hair starts to turn gray, facial wrinkles begin to appear, and their vision and hearing become less sharp. The figure shown identifies several of the effects of aging on the body.

teens and marriage

When teenagers marry, they often face additional challenges compared with those who marry later. The strains of adjusting to a new relationship, earning a living, and completing an education can feel overwhelming. Many married teenagers drop out of school. Without a high-school diploma, it can be difficult to find a good job. Even if both teens work, they may have difficulty earning enough money for rent and food. The couple may end up living with parents or other relatives. Such an arrangement can limit a couple's opportunities to get to know each other, to make decisions, and to develop as a couple. Another difficulty for married teenagers involves changes in their friendships. Unmarried friends may not have the same interests and goals as a married couple, especially if the couple has a baby. A married couple may be concerned about stretching a small income, while single friends may be more concerned about school or dating. It is difficult to know when you are 17 or 18 just how you will feel when you are 25 or 30. People change a great deal during their teens and early twenties. For this reason, many teenagers choose to wait before making a long-term commitment. They want to find out more about themselves, to meet people, and to have other experiences. In spite of all the obstacles, some teenage marriages are successful. The couple must be willing to put in the effort needed to make their marriage work. They need to learn to communicate, to compromise, and to develop the qualities that are important for a fulfilling relationship.

stages of dying

When you think about death and grief, you may first think about the feelings of family and friends left behind when a loved one dies. But people who know they are dying also experience grief. Consider the case of a person who has been diagnosed with a terminal illness. A terminal illness is an illness for which there is no chance of recovery. When the American psychiatrist Elisabeth Kübler-Ross studied the reactions of terminally ill people and their families, she discovered that they typically go through five emotional stages. The five stages of dying are denial, anger, bargaining, depression, and acceptance. Both the dying person and their loved ones may experience these stages. It is important to note that not everyone reacts in the same way. The way people deal with an approaching death depends on their expectations, their emotional strengths, and the reactions of loved ones. Some people do not experience all five stages, and others may experience them in a different order.

abstract thinking

When you were a child, your thoughts and feelings were tied directly to your physical experiences at each moment. For example, you thought about hunger only when your stomach was empty. Now, however, it is easier for you to think abstractly—to consider ideas that are not concrete or visible. For example, you can now think about the problem of chronic hunger in communities around the world. Your growing ability to think abstractly is partly due to the dramatic growth in your brain's frontal cortex.

resisting negative influences

While following the clothing styles of your peers may be harmless, following all of their behaviors may have more serious consequences. Many decisions you will face can affect your health and safety, including decisions about smoking, drinking, drugs, and sexual activity. Parents and other adults may make rules for you early in your teens. Eventually, however, you make these decisions on your own and take responsibility for the results.

responsibilities to yourself

With adolescence come increased privileges. You are treated more like an adult, and you make decisions that direct your life. However, the flip side of privilege is responsibility. You are expected to behave consistently and to assume responsibility for yourself and others. Often the move to this new status is not a smooth one. You may be anxious for the privileges but not so anxious for the responsibilities. Some days you may want to make all your own decisions. Other days you may wish you could hide your head under your pillow and let someone else take charge. Your pathway to adulthood will be marked by a growing responsibility for your own decisions and actions.

energy demands

You may also notice another effect that growth has on your body—it makes you hungry. Your family may remark that your stomach seems to be a "bottomless pit." This is normal during adolescence because you need extra energy to fuel your growing body. It is important, however, to eat nutritious meals and snacks to supply your body with the nutrients it needs. You should not gain excessive weight.

successful marriages

You probably feel, as most people do, that successful marriages are based on love. But what is love? Often young people mistake sexual attraction or short-lived crushes for love. Real love is part of a long-lasting relationship in which people really know, like, and accept each other as they are. People who are truly in love appreciate the things they like about each other and accept the things they dislike. When you love someone, his or her well-being becomes as important to you as your own. Although love is a basic element in a successful marriage, it is not the only one. Love, compatibility, and commitment are key factors in a successful marriage. Compatibility is the ability to live together in harmony. Couples who share many qualities tend to be more compatible. Commitment is the strong determination by the couple to make their marriage a fulfilling lifelong relationship, despite the challenges. Other important factors to consider when thinking about marriage are listed in the figure.

responsibilities to others

Your responsibilities to your family, friends, and community increase greatly during adolescence. At the same time that you are gaining more independence, others may be relying more on you for help.