7.07/7.08 Health

7.08 Childbirth

Childbirth is the process of labor and delivery to bring the baby out of the uterus, through the vagina, and into the world. Childbirth typically lasts 12 to 14 hours, but some women deliver very quickly, while others take 30 or more hours. Many couples in the United States choose to take childbirth classes. These classes prepare both the mother and her partner for recognizing the first signs of labor, feeling secure about what will happen during labor and delivery, and thinking about decisions that might be faced during delivery, such as whether the mother will forego the use of prescription drugs to ease labor pain . Labor, the process of childbirth, begins with these steps: The uterus begins to contract in strong muscular cramps. As labor continues, these contractions become stronger and closer together in time. The thick mucus plug, which has sealed the cervix and protected the uterus, dissolves and is expelled from the body. The woman's "water breaks." This is a popular term for the breaking of the fluid-filled sac in which the baby has been growing inside the uterus. That sac contains amniotic fluid. When a woman's "water breaks," much of that fluid trickles or gushes out of the vagina.

Twins and More

Do you know how twins, triplets, and quadruplets form? Twins can happen in two different ways. Sometimes, after an egg is fertilized, it divides into two separate embryos, and each embryo continues to develop independently. Because they started from the same genetic material, these are identical twins. Other times, a woman may release two eggs from the ovaries instead of one. In this situation, both eggs can be fertilized by two different sperm. These embryos develop into fraternal twins. Twins conceived in this manner can be both boys, both girls, or one boy and one girl. These siblings are no more closely related, genetically speaking, than they would be to any other sibling. Sometimes, twins, triplets, and other multiple fetuses occur because a couple had trouble conceiving, and sought help from doctors who specialize in fertility. The mother may have taken fertility drugs, which may have resulted in the release of several eggs in one month, or she may have undergone in vitro fertilization (IVF), a process in which eggs are fertilized in a laboratory and the fertilized eggs are implanted into her uterus. Usually, several fertilized eggs are inserted into the uterus because many of them will not successfully implant and survive. Because of this procedure, women who have undergone IVF can end up with twins, triplets, quadruplets, or even more babies in a single pregnancy.

Third Trimester

During the final three months of pregnancy, the fetal systems continue to grow and develop. The last system to fully develop is the respiratory system. During this trimester, the fetus's eyes open, and he or she makes sucking movements (often on the thumb and toes) as a reflex to prepare for breastfeeding. The third trimester is the time of the greatest weight gain. Most babies weigh between 6 and 9 pounds at birth.

First Trimester

During the first 12 weeks of pregnancy, all of the baby's body structures and systems develop. For the first six to eight weeks, the growing organism is called an embryo; after eight weeks and for the rest of the pregnancy, it's called a fetus. By the end of the first trimester, the fetus has arms, legs, feet, toes, and fingers. The heart and central nervous system are formed, and male or female sex organs are formed as well. At the end of the first 12 weeks, the fetus is approximately four inches long and weighs about one ounce. The first trimester is the riskiest time of the pregnancy. This is the time when miscarriage (spontaneous expulsion of the fetus) is most likely, and it's also the time when birth defects most commonly occur. Birth defects, or damage to the growing fetus, can happen for many reasons. Genetic defects, such as Down syndrome, may result in mental or physical disabilities. Pregnant women should avoid using drugs, smoking cigarettes, or drinking alcohol, all of which risk damaging the developing fetus.

First Stage

During the first stage of childbirth, the cervix thins out and gradually stretches open to 10 centimeters (about the size of a bagel) in order to allow the baby's head (the largest part of the baby) to pass into the vagina. This opening of the cervix is called dilation. This stage usually has the most intense contractions, and many women experience chills, vomiting, and irritability. If a woman decides to use drugs to ease the pain of labor, they are administered during this stage.

Other Birth Considerations

Every Mom Deserves Support Partners can share and support one another through the process of delivery. Even though a woman does the intense physical work of childbirth, her partner, family members, childbirth coach, and/or midwife (a health-care provider trained to assist women during childbirth) can provide helpful support and encouragement. During childbirth, they can help with breathing and relaxation techniques. Some women choose a traditional hospital for childbirth; others pick an alternative birthing center, or choose to have their delivery at home, often with the assistance of a midwife. Whichever the decision, plans should be made in advance about what to do if problems occur. On one hand, delivering a baby is as natural as anything can be. On the other hand, for any individual, it doesn't happen often and can be stressful and, in some instances, risky. Recognizing the Possibility of Problems Hospitals are best equipped to handle some of the complications or problems that might arise during childbirth. Sometimes the baby is in a breech position (that is, the baby exits with feet or buttocks first, rather than the normal head-first position); sometimes there is extensive bleeding and the mother is in danger; and sometimes the baby's umbilical cord can get caught around his or her neck during labor, cutting off the oxygen flow. In these and other cases, a woman and her baby need qualified medical attention. In some cases, like those described above, the baby might be delivered through a surgical procedure called a Cesarean section, or "C-section." During a C-section, an incision is made through the mother's abdomen and through the front of the uterus. This opening allows the baby to be grasped and pulled from the mother's uterus. The baby is born without ever passing through the vagina. If a woman has regular checkups during her pregnancy, she and her doctor may know if a Cesarean section will be required or likely, and can be prepared in advance.

Fertilization and Implantation

Fertilization occurs when a sperm cell and an egg meet during a specific phase in the woman's menstrual cycle. Exactly how does fertilization occur? Watch the slide show to learn about the process of fertilization. Look for the key term zygote. Click the arrows to advance or review slides.

Pregnancy

How does a woman know she's pregnant? For many women, the first sign of pregnancy is missing a period. Because the uterus needs the tissue lining to nourish the growing embryo, it doesn't shed it as it normally would during the menstrual cycle. Other symptoms of early pregnancy may include swollen or tender breasts and nausea (stomach upset), especially early in the morning (sometimes called "morning sickness "). If a woman thinks she may be pregnant, she can check by using a home pregnancy test that can be bought at a drug store without a prescription. These tests detect a hormone that is present in a woman's urine during the first few months of pregnancy. If the test is positive, indicating pregnancy, the woman should then visit a doctor or clinic as soon as possible to confirm the pregnancy. If a woman has a negative test but still feels she might be pregnant, a doctor or health-care provider can do a pelvic exam (feeling the size of the uterus) or a blood test to find out for sure. A 40-Week Process The duration of a pregnancy is measured from the first day of a woman's last menstrual period prior to conception, with the expected period of gestation averaging 40 weeks. (Gestation is the process of development within the uterus from conception until birth.) Normal, healthy births usually take place between the 38th and 42nd weeks. Deliveries before the 38th week are considered premature (early), and after 42 weeks labor may be induced (brought on with drugs). Pregnancies are divided into trimesters (three-month sections); each trimester has unique characteristics.

Second Stage

In the second stage of childbirth, known as delivery, the baby is actually pushed out of the vagina. For some women, this stage only lasts for a few pushes; for other women, this stage may involve one hour or more of pushing. Sometimes, when the baby is coming out of the vagina, the skin around the labia and between the labia and anus may be torn. In some cases, the delivering the health-care provider performs an episiotomy, a procedure in which the skin is cut before it tears. Some people think episiotomies are unnecessary; the procedure is an option that women should consider and discuss with their partner and health-care provider before labor begins.

Pregnancy and Birth

In this lesson, you'll learn about fertilization and conception. You'll also learn about the stages of pregnancy, labor, and childbirth.

Fertilization and Conception

Now that you're familiar with both the female and male reproductive organs, as well as the processes of ovulation and menstruation, it's time for a more complete explanation of how pregnancy occurs. As explained earlier, a woman typically releases one egg a month from one of her ovaries into the fallopian tube. Little hairs inside the fallopian tube, called cilia, help the egg slowly float down the tube toward the uterus. Typically, the egg lives for only one day after its release from the ovary. For fertilization—a union of the egg and sperm—to take place, sperm must reach that egg during this time. Unlike the egg, sperm can live for up to three to five days inside the woman's body, so the woman is fertile, or capable of getting pregnant, for a few days each month. It's very difficult to know exactly when these few days fall, however, because some women have irregular menstrual cycles. During sexual intercourse, when a man ejaculates inside a woman's vagina, he releases about 300 to 400 million sperm that begin their journey toward the fallopian tubes. Sperm contain genetic materials in their "heads" and have long "tails" that help them swim through the uterus. The acrosome , a cap-like structure on the head of a sperm cell, helps the sperm penetrate the egg. One sperm will penetrate the outer membrane of the egg. When fertilization occurs, the genetic material in the sperm's head joins with the genetic material in the egg's nucleus. As the fertilized egg travels down the fallopian tube, it begins a process of rapid growth and cell division. It can take five to seven days to reach the uterus, where, thanks to the buildup of extra tissue during the menstrual cycle, the fertilized egg may implant in the uterine wall. When this happens, we say that conception has occurred. In other words, once the fertilized egg is implanted, the woman has conceived—she is pregnant. Once the process of cell division begins to occur, the fertilized egg is called an embryo. After about eight weeks of development, the embryo is called a fetus .

Second Trimester

The second trimester includes the 12th through the 24th weeks of pregnancy (the third through sixth months). It is marked by the growth and development of the fetus's organs and body systems. Hair forms on the fetus's head and eyelashes, and eyebrows appear. Around the 16th week, the mother can start feeling the fetus's movements. By the end of the second trimester, the average fetus is almost 12 inches long and weighs between 1 and 1.5 pounds. At the end of the 24th week, most fetuses are capable of living outside the womb, but only with proper intensive care in a hospital.

Third Stage

The third stage of childbirth is the afterbirth. During this stage, the placenta and the umbilical cord are delivered. (In the womb, the fetus is connected by the umbilical cord to the placenta, a mass of blood vessels and other tissue that grows in the uterus during pregnancy to provide nutrients and oxygen to the fetus.) Before the expulsion of the placenta during the afterbirth, the umbilical cord is cut at the baby's abdomen (where we each have a belly button) but remains attached to the placenta at the other end. Delivery of the afterbirth usually takes only 10 to 15 minutes.

Medical Specialists for the Reproductive Needs of Women

There are several kinds of doctors who specialize in different facets of women's medical reproductive needs. Although a woman may routinely see a generalist or internist for the supervision of her overall health, she also may see a gynecologist, obstetrician, and pediatrician. Let's find out more about some of these specialists: Internist. A doctor with special training in the prevention and treatment of adult diseases Gynecologist. A doctor who specializes in treating diseases of the female reproductive organs Obstetrician. A doctor who specializes in pregnancy and childbirth OB/GYN. A doctor with combined expertise in gynecology and obstetrics Pediatrician. A physician who specializes in the care of babies and children Midwife. Historically, a midwife was a woman who assisted in childbirth. Today, a midwife is a man or woman who is a licensed specialist in pregnancy and childbirth and who helps women before and during and delivery, and also during the postpartum period (the time following childbirth). Often, a midwife works as part of a team with an OB/GYN and pediatrician.

Prenatal Care and Prenatal Screening

Women are much more likely to have a normal delivery and a healthy baby if they eat a well-balanced diet, get regular physical activity, and have regular prenatal care. ("Prenatal" means "before birth.") Prenatal care includes regular visits to an obstetrician (a doctor who specializes in the care of women during pregnancy and childbirth), who can use screening tools to make sure the fetus is developing normally. At every prenatal visit, the uterus is measured to ensure that the fetus is growing at the anticipated rate. The woman's blood pressure is taken to watch for signs of hypertension. Prenatal visits also are the perfect time for a woman or her partner to ask questions about the pregnancy and upcoming birth.

Drug Use During Pregnancy

Women should not take any kind of drugs or medication during pregnancy unless specifically directed to do so by their doctor. Because the mother's health directly affects the health of the developing fetus, pregnant women should never smoke cigarettes, drink alcohol, or take illegal drugs during pregnancy. Cigarette smoking reduces the amount of oxygen in the bloodstream; babies born to women who smoke tend to have a lower birth weight and more breathing problems after birth, such as asthma or emphysema, and are at higher risk for sudden infant death syndrome (SIDS, which is the sudden death of a child before age 1, with no apparent cause or explanation)). Women who drink alcohol during pregnancy put their babies at risk of fetal alcohol syndrome (FAS). Children with FAS often have smaller-than-average heads and brains, distorted facial features, sleep disorders, hyperactivity, and mild to severe mental challenges. Babies exposed to illegal drugs during pregnancy, such as cocaine or heroin, may be born addicted to those drugs, and also are at risk of physical and mental disabilities.