Pregnancy, Complications of
Pregnancy is the period of time between conception (kun-SEP-shun) and birth. A full-term pregnancy lasts 9 months and usually does not involve major health problems. Sometimes, however, complications develop that jeopardize the health of mother and baby.
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What Is Pregnancy?
Pregnancy is the interval of time beginning when an egg and sperm unite and ending when a baby is born. A full-term pregnancy lasts 9 months (38 to 40 weeks). The 9 months are divided into trimester * one (the embryo * develops), two (the embryo turns into a fetus * ), and three (the fetus gains weight and gets ready for birth).
* trimester (tri-MES-ter) is any of three periods of approximately 3 months each into which a human pregnancy is divided.
* embryo (EM-bree-o), in humans, is the developing organism from the end of the second week after fertilization to the end of the eighth week,
* fetus (FEE-tus) in humans, is the unborn offspring in the period after it is an embryo, from 9 weeks after fertilization until birth.
* anemia (a-NEE-me-a) results when people have too few red blood cells to carry oxygen in the blood.
What Are the Normal Discomforts of Pregnancy?
As a woman gains weight and her body changes to accommodate a growing fetus, she may experience some of the following signs or symptoms:
- Anemia *
- Bleeding gums
- Breast tenderness
- Edema (water retention)
- Food aversions and cravings
- Frequent urination
- Hemorrhoids *
- Nausea and vomiting
- Stretch marks *
- Varicose veins *
Symptoms vary from woman to woman, and even between pregnancies for an individual woman.
What Are the Common Complications of Pregnancy?
Most women get through pregnancy and giving birth without any major health problems. However, a few experience complications that threaten the health of both mother and baby. These problems can be very frightening, and they are hard to deal with when they result in the loss of a baby.
Morning sickness refers to nausea and vomiting, and it is misnamed. Some women have it in the morning, others at noon, and still others at night. Some women feel queasy only occasionally, whereas others feel sick all day long. Overall, about half of all pregnant women experience some degree of morning sickness, but it usually subsides on its own after about the third month of pregnancy. Only rarely does it require medical attention. No one knows what causes morning sickness, but probably it is related to the hormonal and other chemical shifts that occur in early pregnancy.
* hemorrhoids (HEM-o-roidz) are a mass of dilated veins in swollen tissue at the margin of the anus or nearby within the rectum.
* stretch marks are stripes or lines on the skin (such as on the hips, abdomen, and breasts) from excessive stretching and rupture of elastic fibers, especially due to pregnancy or obesity.
* varicose veins (VAR-i-kose VAYNZ) are abnormally swollen or dilated veins.
Miscarriage (MISS-care-ij) is also called spontaneous abortion, and it means that suddenly the pregnancy terminates on its own. Bleeding, cramping, and abdominal pain often signal a miscarriage. Most miscarriages occur before the fourteenth week of pregnancy, which is why many women wait to tell their family and friends about a pregnancy until they have passed the 3-month mark. Occasionally, a woman will have a "late" miscarriage, which means that it occurs during the second trimester. After the twentieth week, the unexpected end of a pregnancy is called stillbirth if the baby is born dead and premature birth if the baby is alive but born before the thirty-seventh week.
Scientists estimate that as many as 40 percent of pregnancies end in miscarriage, although most of these occur so early that a woman may not even realize that she is pregnant. Early miscarriages often occur when the body naturally rejects a fetus that is not developing properly. Later miscarriages are much less common. Reasons for late miscarriages include a placenta * that is improperly attached to the uterus * , the placenta separating from the wall of the uterus for some reason, and other causes.
Gestational * diabetes * is a type of diabetes that occurs when a woman does not produce enough insulin to handle the increased blood sugar that accompanies pregnancy. Any woman can develop this common problem, but women who are older, are over-weight, and who have relatives with diabetes are at higher risk. A special diet often can control the problem without medication. Untreated diabetes during pregnancy increases the risk of certain birth defects. Such infants often have abnormally high birth weights and are prone to developing low blood sugar in the hours after birth. Most cases of gestational diabetes are temporary and disappear after the baby is born.
* placenta (pla-SEN-ta) in humans is the organ that unites the fetus to the mother's uterus.
* uterus (YOO-ter-us) in humans is the organ in females for containing and nourishing the young during development in the period before birth. Also called the womb.
* gestational (jes-TAY-shun-al) means relating to pregnancy.
* diabetes (dy-a-BEE-teez) is an impaired ability to break down carbohydrates, proteins, and fats because the body does not produce enough insulin or cannot use the insulin it makes.
* fallopian tube (fa-LO-pee-an tube) is either of the pair of long slender tubes connecting the ovaries to the uterus. Typically, a fallopian tube is where conception takes place.
Acesarean section is the method of delivering a child by opening the abdomen and uterus. It is performed when natural delivery presents risk to the mother or child.
The name of the procedure comes from the traditional story that the Roman ruler Julius Caesar (100-44 B.C.E.) was delivered by cesarean. More likely is the explanation that Cesarean law forbade the burial of a deceased mother before the baby was delivered.
Written accounts of the rescuing of an infant from its dead mother were recorded as early as 500 B.C.E. Cesarean sections were known to have been practiced by the ancient Romans, Indians, and Jews in the Roman era.
An ectopic (ek-TOP-ik), or tubal, pregnancy is one in which the fertilized egg begins to develop outside of the uterus, usually in a fallopian tube * . Cramps, nausea, dizziness, tenderness in the lower abdomen * , and light vaginal bleeding often accompany ectopic pregnancies. Early detection and treatment of an ectopic pregnancy are essential. If the embryo continues to grow, eventually it will burst the fallopian tube and damage it permanently. An undiagnosed ectopic pregnancy can also seriously jeopardize the health of the mother.
An ultrasound * can be used to examine the abdomen and confirm the diagnosis of an ectopic pregnancy. An ultrasound sends sound waves into the body that bounce off internal structures. A computer converts the returning sound waves into an image of the internal structures. Ectopic pregnancies usually are removed surgically.
An incompetent cervix * is the cause of about 25 percent of late miscarriages. The cervix is the muscular opening of the uterus into the vagina (va-JY-na). An incompetent cervix means that it opens too early because of the pressure exerted by the growing fetus. An incompetent cervix can be caused by many factors, including a genetic tendency for it, stretching or tearing of the cervix during previous deliveries, and carrying multiple fetuses. An incompetent cervix can be treated by stitching the cervix closed during the second trimester or by bed rest for the last several months of pregnancy.
Preeclampsia/eclampsia and toxemia
The terms "preeclampsia/eclampsia" and "toxemia" are used interchangeably to mean the same thing: pregnancy-caused hypertension (high blood pressure). Most cases of toxemia are characterized by high blood pressure; swelling of the face, hands, and ankles; too-rapid weight gain; headaches; and protein in the urine. When left untreated, toxemia can cause nausea, vomiting, blurred vision, convulsions * , and coma * .
Toxemia most often affects young women during the last months of their first pregnancy, and the cause is unknown. Often, treatment involves hospitalization until the blood pressure returns to normal, followed by limited activity and sometimes bed rest at home.
Placenta previa (PREE-vee-a) means that the placenta is lying low in the uterus. It can be dangerous if the placenta actually covers the cervix during labor and delivery. The baby still requires the blood, oxygen, and nutrients provided by the placenta during birth, and so the placenta should be the last thing out. Placenta previa can lead to premature labor, and women with this problem sometimes must limit their activity or stay in bed until the baby is born. Doctors can monitor the position of the placenta using ultrasound. When it is time to have the baby, doctors opt for a cesarean section * if the placenta is still covering or very close to the cervix.
* abdomen (AB-do-men), commonly called the belly, is the portion of the body between the thorax (THOR-aks) and the pelvis.
* ultrasound is a painless procedure in which sound waves passing through the body create images on a computer screen.
* ovaries (O-va-reez) are the sexual glands from which eggs (ova) are released in women.
* sperm are the tiny, tadpole-like cells males produce in their testicles (TES-ti-kulz) that can unite with a female's egg to result eventually in the birth of a child.
* umbilical cord (um-BIL-i-kul KORD) is a cord arising from the navel that connects the fetus with the placenta.
* cervix (SER-viks) is the lower, narrow end of the uterus, which opens into the vagina.
* convulsions (kun-VUL-shunz) are violent involuntary contractions of muscles normally under voluntary control.
* coma (KO-ma) is an unconscious state, like a very deep sleep. A person in a coma cannot be awakened, and cannot move, see, speak, or hear.
* cesarean section (si-ZAR-ee-an SEK-shun) is the surgical incision of the walls of the abdomen and uterus to deliver offspring in cases where the mother cannot deliver through the vagina.
Preterm labor and premature birth
More babies are born past their expected due date than before it, but in the United States, 7 to 10 out of 100 babies are born prematurely. A premature birth means delivery before the thirty-seventh week of pregnancy. About one-third of premature babies are born early because the mother went into labor too soon (the other cases occur because the amniotic sac * ruptures prematurely or because a health problem with the mother or baby requires early delivery).
Among the many risk factors for preterm labor are smoking, alcohol use, drug abuse, vitamin deficiencies, a job that requires standing for long time periods, infections like German measles, placenta previa or other physical causes, and poor nutrition.
Preterm labor that results in a premature birth poses serious health problems for the baby who has not finished developing inside the uterus.
Are There Risk Factors for Pregnancy Complications?
Older women (over 35) have a higher probability than younger women of experiencing high blood pressure, diabetes, and cardiovascular disease while pregnant, but these conditions are controllable with good medical care. Older women also are more prone to miscarriage, preterm labor, and postpartum (after birth) bleeding, and they have an increased risk of having a child with birth defects.
On the other end of the age spectrum, teen mothers are twice as likely to have premature babies and babies with low birth weight than are older mothers. Teenagers also are prone to premature labor, prolonged labor, toxemia, and anemia. About 1/3 of pregnant teens do not receive adequate medical care during pregnancy (as compared with about 1/4 of older women). Finally, while the chance of dying from pregnancy-related complications is very low overall, the rate is much higher in women younger than 15 than in women older than 15.
Can Pregnancy Complications Be Prevented?
Many complications of pregnancy develop in healthy mothers for unknown reasons. However, if a woman is in poor health before becoming pregnant, the likelihood of having complications is higher than usual. Regular prenatal * care, or medical care during pregnancy, is very important, because it allows doctors to detect and treat problems with mother or baby as early as possible.
A Primer of Pregnancy
Pregnancy begins when an egg and sperm unite and ends when a baby is born. The usual sequence of events is as follows:
- An egg is released from one of the two ovaries * .
- The egg travels down the fallopian tube toward the uterus.
- If sperm * are present during this time, the egg may be fertilized while in the fallopian tube.
- The fertilized egg continues down the fallopian tube into the uterus, where it implants into the lining of the uterus. The placenta develops, rich with blood and nutrients, and nourishes the embryo. The embryo is attached to the placenta via the umbilical (um-BIL-i-kul)cord * .
- After about 3 months, the embryo has developed the basic human structural plan and is called a fetus.
- The fetus continues to develop inside a fluid-filled sac in the uterus called theamnion(AM-nee-on).
- After 38 to 40 weeks, the baby is delivered through the vagina (the tubular structure connecting the uterus to the outside of the body) or through an incision in the abdomen and uterus (a cesarean section).
* amniotic sac (am-nee-OT-ik SAK) is the sac formed by the amnion, the thin but tough membran e outside the embryo, which lines the outermost embryonic membrane and contains the embryo and later the fetus, with the amniotic fluid around it.
* prenatal (pre-NAY-tal) means existing or occurring before birth, with reference to the fetus.
Chism, Denise M. The High-Risk Pregnancy Sourcebook. Los Angeles: Lowell House, 1998.
Eisenberg, Arlene, Sandee E. Hathaway, and Heidi E. Murkoff. What to Expect When You're Expecting, revised edition. New York: Workman Publishing Company, 1996.
Jovanovic-Peterson, Lois, and Morton Stone. Managing Your Gestational Diabetes: A Guide for You and Your Baby's Good Health. Minnetonka, MN: Chronimed, 1998.
Rich, Laurie A. When Pregnancy Isn't Perfect: A Layperson's Guide to Complications in Pregnancy, third edition. Rhinebeck, NY: Larata Press, 1996.
Sears, William, and Martha Sears. The Birth Book: Everything You Need to Know to Have a Safe and Satisfying Birth. New York: Little Brown, 1994.
U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road
N.E., Atlanta, GA 30333. The U.S. government authority for information
about infectious diseases and other health disorders, the CDC posts
information about the complications of pregnancy at its website.
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How Common Are the Common Pregnancy Complications?
The approximate percentage of pregnant women affected by the common complications of pregnancy are listed below:
- Ectopic pregnancy: 2 percent.
- Gestational diabetes: I to 10 percent.
- Miscarriage: as many as 40 percent of pregnancies end in miscarriage, often before a woman even knows she is pregnant. Of confirmed pregnancies, about 10 percentend in miscarriage.
- Morning sickness: 50 percent; severe nausea and vomiting that require medical care occur in less than 0.5 percent of pregnancies.
- Placenta previa: 1 percent.
- Premature birth: 7 to 10 percent of deliveries; about 1/3 of these are caused by preterm labor.
- Preeclampsia/Toxemia: 5 to 10 percent.