Pregnancy and Birth

3rd 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.

Prenatal Care

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.

Complications

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 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.

Fertilization

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 . It takes about six days for a fertilized egg to become a multicellular embryo.

Labor

1st 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. 2nd 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. 3rd 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.

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. 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.

Drug Use in 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.

Pregnancy + Development - 1st Trimester

In the 1st trimester, the central nervous system, heart, and male/female sex organs are formed. At the end of the first 12 weeks, the fetus is approximately four inches long and weighs about one ounce. Miscarriage and birth defects are most likely to occur within the 1st trimester. 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.

Medical 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.

Pregnancy

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. 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.

2nd 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.

Twins

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. 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. In vitro fertilization (IVF), a process in which eggs are fertilized in a laboratory and the fertilized eggs are implanted into her uterus. That can result in twins, triplets, etc.