Pregnancy: Potential Complications

very woman who is about to have a baby hopes the entire 9 months will be healthy and trouble­free. For 10 to 20 percent of pregnancies, however—about 875,000 a year in the United States alone—one or more conditions arise to complicate matters. Obtaining good medical care, preferably starting before the pregnancy even begins, is the best way to ensure a safe journey through pregnancy. After identifying any potentially dangerous conditions, the doctor will take every step possible to protect both mother and baby.

What constitutes a “complication”? Simply put, it's any condition that might endanger the health and safety of mother, baby, or both. Being considered at “high risk” merely alerts you (and your doctor) to watch carefully for danger signs and do all you can to prevent trouble. Pregnancy, labor, and delivery can still proceed normally, and the baby is likely to be just fine.

Why is the outlook so much better now than it once was? First, doctors know what to look for. Second, many tests are available to assess suspected problems. (See chapter 24, “Prenatal Tests to Consider.”) Third, if the mother­to­be follows her doctor's instructions, many of the complications of pregnancy will not affect the baby and will disappear after delivery.

Physicians and midwives have been trained to recognize danger signs early in pregnancy. They can even take some preventive measures beforehand. Since overweight causes difficulties in pregnancy, for example, doctors often advise heavy women to shed pounds before they conceive. Women suspected of carrying the gene for a hereditary disease may choose to undergo genetic testing and counseling while they are still considering pregnancy.

Your obstetrician can also tap the expertise of a specialist, such as a perinatologist, who routinely handles medical problems during late pregnancy and immediately after birth. A neonatologist, a pediatrician who works exclusively with newborns, can be called in to advise about problems that occur (or are expected to occur) shortly after delivery. Women who develop gestational diabetes, a blood sugar condition that begins during pregnancy, may need to see both a diabetologist and an obstetrician regularly throughout pregnancy.

If you are told that your pregnancy is “complicated” or “high risk,” don't panic. Keep in mind that even an “uncomplicated” pregnancy isn't necessarily problem­free. In fact, most so­called normal pregnancies involve physical discomfort. Your body undergoes many changes to create a small but cozy space in which the baby can flourish until it's out on its own.

When you (and your partner) first learn that pregnancy is going to be “complicated,” you'll naturally feel frightened and depressed. The best way to allay those feelings is to learn as much as you can about your particular problem.

Ask your doctor for pamphlets or a list of suggested books. Call a professional association or self­help group such as those listed at the end of this book. Ask your hospital's medical librarian for recent articles on the subject. Perhaps your doctor or a nurse in the obstetrics department of your hospital can put you in touch with a woman who has gone through the same difficulties.

Think through your pregnancy realistically. When choosing an obstetrician, remember that the distance from your home to the doctor's office and the hospital could become important in case of an emergency. Since you'll rely on your doctor for continued reassurance, education, and support, make sure you're on the same wavelength. If he or she recommends bed rest for days, weeks, or even months, don't hesitate to look for assistance with your everyday responsibilities. One not­for­profit organization that specializes in advising women who need extended bed rest is Sidelines. (See “Directory of Support Groups” at the end of this book.)

Be alert for any condition that might cause the baby to be born early. Prematurity is the cause of 85 percent of neonatal injury and death in the United States. That helps explain why your doctor wants your pregnancy to last as close to the full 40 weeks as possible. The “magic number” is 36 weeks. At that point the baby's lungs have matured enough to allow it to breathe on its own. Babies born before 33 to 34 weeks usually must rely on a respirator or other assisted breathing for a while.

Symptoms such as bleeding are important warning signs that something may be wrong. They provide an opportunity to seek medical care and make things right. Think of your high­risk pregnancy as a high­awareness pregnancy.

When the Baby is Lost

Some circumstances make an end of the pregnancy inevitable. They include:

Ectopic (“Out­of­Place”) Pregnancy

In this situation, the embryo becomes implanted outside its rightful place—the uterus—most often in the fallopian tubes. The usual symptoms are lower abdominal pain and bleeding. Since such an embryo could endanger your life if allowed to grow, your doctor must remove it surgically as soon as possible after diagnosis. You are more likely to have an ectopic pregnancy if you have had a pelvic inflammatory disease or other sexually transmitted disease, have had an ectopic pregnancy previously, or have undergone previous tubal surgery. You are also at greater risk if your mother took the anti­miscarriage drug DES.

Miscarriage

At least 10 to 30 percent of pregnancies end in miscarriage (loss of the fetus before the 20th week of gestation). It usually happens even sooner—by the tenth week—when you may not even realize you're pregnant. In most miscarriages (85 percent), a genetic disorder in the egg has made it impossible for the fetus to develop normally. Other causes include congenital abnormalities; infection; and exposure to drugs or chemicals. Because any woman who has had 3 or more miscarriages in a row is said to be prone to “recurrent miscarriage,” all her subsequent pregnancies are classified as high risk and must be monitored closely.

Risk factors for a miscarriage include early or late pregnancy (age under 18 or over 35); endometriosis; placental abruption (see below); uterine infection from a sexually transmitted disease or another cause; fibroid tumors or uterine scar tissue; malnutrition; exposure of either parent to radiation or toxic chemicals; smoking; excessive alcohol intake; previous miscarriages; and hormone problems. For more information see chapter 27, “What To Do When Miscarriage Strikes.”

Extreme Prematurity

This is usually defined as birth at less than 24 weeks. High­tech neonatal intensive­care units are saving increasingly smaller infants, but they can't save the tiniest ones.

Molar Pregnancy

In this rare condition, clinically called a hydatidiform mole, the fertilized egg degenerates and the placenta deteriorates into a mass of tissue that a doctor must remove by surgery, vacuum extraction, or other means. Risk factors include a maternal age of less than 20 or more than 40, chromosomal abnormalities, hormone imbalance, and possibly nutritional deficiencies. A woman who thinks her pregnancy is progressing normally may realize she has a problem because of nausea or bleeding. The doctor may notice that her uterus seems too large for the length of her pregnancy; that she has high blood pressure, fluid buildup, and too much protein in her urine—all signs of a dangerous condition called preeclampsia; and that there are no fetal heart sounds. Molar pregnancy is usually diagnosed in the second, third, or fourth month, usually by ultrasound.

Troublemakers Part I:
Maternal Health Problems

Any woman who has had problems with a previous pregnancy, whether it resulted in a healthy child or not, is considered at risk in subsequent pregnancies. If a close blood relation, especially her mother, had a problem pregnancy, the doctor may judge that a risk factor as well, though it is highly unlikely that exactly the same problem would occur.

Even if you've had no previous problems, there are numerous medical conditions you might have that could affect the unborn baby.

Common diseases, infections, chemical imbalances, and other health factors pose special dangers for the fetus unless they are carefully controlled. That's why you need close medical attention throughout your pregnancy.

Diabetes Mellitus

This condition, in which your body lacks sufficient insulin to process the sugars it relies on, can cause numerous complications. Without adequate medical treatment, it poses an increased risk of birth defects, very large babies (more than 9 or 10 pounds at birth), too much amniotic fluid (hydramnios), pregnancy-induced high blood pressure (preeclampsia), respiratory distress syndrome in the baby, miscarriage, premature birth, and stillbirth. About 1 to 2 percent of pregnant women have diabetes mellitus before becoming pregnant; some develop it during pregnancy (gestational diabetes). Routine testing of all pregnant women is usually done at 24 to 28 weeks of gestation.

Part of the usual treatment for diabetes, whether chronic or gestational, is a diet carefully regulated to remain low in sugar. Many women learn how to monitor their own blood sugar levels at home every day with a blood glucose meter or strips (available at many pharmacies and home health supply stores). One small drop of blood is enough for such tests. If necessary, a woman can control her blood sugar level with diet (frequent small meals), exercise, and self­injected insulin. She can also perform simple urine tests with dipsticks (specially treated paper strips) at home. Other tests sometimes given to women with chronic or gestational diabetes to assess the health of the baby include fetal nonstress tests and alpha­fetoprotein tests (see chapter 24, “Prenatal Tests to Consider”).

If you have diabetes mellitus, you may need brief hospitalization to stabilize blood glucose levels, especially immediately after the condition has been diagnosed. The doctor may decide to perform a cesarean section or induce labor before 40 weeks of gestation if your condition or the baby's condition warrants that step. You can take insulin safely during pregnancy, although you should not use the oral diabetes medications tolbutamide (Orinase) and chlorpropamide (Diabinese), which increase the risk of fetal defects.

High Blood Pressure

High blood pressure during pregnancy is a leading cause of fetal loss in midterm and late pregnancy. If untreated, high blood pressure can cause the baby to grow inadequately, to be born prematurely, and to undergo fetal distress during labor. It also can seriously threaten the mother's health.

About 7 percent of pregnant women have high blood pressure. Your chances of developing it are greatest during your first pregnancy, especially if you're a teenager or over 30, are overweight, or have a history of hypertension. Other risk factors include diabetes, multiple births (such as twins or triplets), too much water in the amniotic sac surrounding the fetus and lack of prenatal care.

An early tipoff to high blood pressure is any sign of fluid retention, such as a puffy face or swollen fingers, blurred vision, or severe headaches. Other symptoms are pain in the upper abdomen and a weight gain of more than 2 or 3 pounds in 1 week during the last month of pregnancy.

All pregnant women should have a routine blood pressure reading at each visit to the doctor. If you seem to be developing problems your doctor may ask you to return to the office for more frequent readings or may teach you to take your blood pressure at home. Treatment may include blood pressure medications, such as methyldopa (Aldomet) and hydralazine (Apresoline); but you should not take Reserpine (Diupres, Hydropres, others) and propranolol (Inderal, Inderide) during pregnancy, unless absolutely necessary. Lying in bed, especially on your left side, promotes blood supply to the kidneys and uterus. Doctors recommend a high­protein, low­salt diet and forbid all smoking.

If you already have high blood pressure, it raises your chances of developing the condition known as preeclampsia. In addition to hypertension, the symptoms of this serious condition include water retention and protein in the urine, indicating a kidney problem. As a result, the baby may be premature, underweight, and weak due to poor nutrition and a shortage of oxygen. The doctor may prescribe dietary changes and bed rest, as well as medications such as magnesium sulfate and phenotoin (Dilantin) to prevent possible seizures. Delivery may be scheduled as soon as it's safe for the baby.

Untreated preeclampsia is a life­threatening condition that can damage the mother's kidneys, liver, eyes, and brain and may lead to coma or convulsions (eclampsia). Between 3 and 5 percent of pregnant women with eclampsia die; 20 percent of their babies suffer the same fate. Fortunately, women who receive close medical attention throughout their pregnancies rarely develop the problem. Typically, eclampsia is discovered when a woman who has had uncontrolled high blood pressure throughout pregnancy arrives at the emergency room to give birth without the benefit of any prenatal care.

Kidney Disease

Diseases of the kidney—relatively rare in pregnancy—may be caused by lupus, diabetes, or an untreated bladder infection. The mother may develop high blood pressure, and other dangerous conditions, and the baby may be born prematurely. Fever, flank pain, or blood in the urine—the chief symptoms of kidney infection—require immediate medical care.

Heart Disease

Extra weight and water retention—common during pregnancy—make the heart pump harder. A pregnant woman with heart disease should call the doctor immediately if she experiences any dizziness, discomfort, or pain. She should be sure to include adequate iron and folic acid in her diet and restrict her salt intake. The obstetrician will exercise special caution when prescribing medications and may ask a heart specialist (cardiologist) to help oversee the pregnancy.

Sickle­Cell Anemia

Advances in the treatment of this disease, which almost exclusively attacks blacks, has greatly improved the chances of a successful pregnancy. Pregnant women may need blood transfusions every 1 to 3 weeks, starting in the first trimester. Urinary tract infections are twice as common in women with the sickle­cell gene, and these infections must receive prompt treatment.

Lupus

Systemic lupus erythematosus (SLE) is called an autoimmune disorder because the body attacks its own connective tissue. The rate of miscarriage and fetal loss in women with SLE is much higher than average. Flareups are common both during pregnancy and after childbirth, although remission is possible. Sometimes diagnosis only comes after repeated miscarriages.

Thyroid Imbalance

About 1 in 200 pregnant women have hyperthyroidism; their thyroid glands produce too much hormone. Those with too little hormone (hypothyroidism) are sometimes infertile; but when pregnancy occurs, they can receive medical treatment to help prevent miscarriage and any problems with the baby. Children born to women with thyroid imbalance typically have low birth weight.

PKU

Phenylketonuria is a congenital condition that can lead to mental retardation and seizures when left untreated. If a mother­to­be has this condition it can leave the baby with birth defects—small brain, mental retardation, and heart problems—or miscarriage. Any woman who was born in a U.S. hospital since the 1960s should have had a PKU test at birth. To reduce the danger to a developing baby, who may inherit the disorder in any case, doctors prescribe a low­phenylalanine diet prior to conception. Among other things, the mother should be especially careful to avoid aspartame (Nutrasweet), which releases phenylalanine after being digested.

Epilepsy and Other Seizure Disorders

Pregnancy changes the metabolism and balance of hormones in the body, altering the response to medication and increasing the probability of seizures in women with epilepsy. According to the Epilepsy Foundation of America, women taking epilepsy medications also have a 2 to 3 times greater risk of bearing a child with a birth defect. If the doctor thinks it's advisable, a woman who has had no seizures for a long time and wants to become pregnant can stop taking her medication briefly to see what happens. Sometimes however, there is no choice but to continue the drugs, whether she's pregnant or not. In any event, genetic counseling and prenatal testing are advisable. Close monitoring throughout the pregnancy is vital.

Age

Age is considered a risk factor because many problems are more likely to occur before age 20 or after age 35. For example, the chance that the baby will have Down syndrome is 9 times greater at 40 than at 30—although even at the increased rate, it's still less than 1 percent. At age 45, however, the incidence of Down syndrome increases to 3 percent. Diabetes and high blood pressure strike 1.3 percent of pregnant women under 35 but 6 percent of those over 35. Labor tends to last longer after age 35, and the chances of having twins or triplets increases. First births between ages 30 and 39 have doubled in the past 15 years, and those in women over age 40 have increased by 50 percent; so more and more pregnant women find themselves in the high risk category.

Viral Infections

Infections caused by viruses are hard to treat and threaten potentially serious problems to the baby.

Rubella (German measles). A fairly innocuous illness in itself, rubella during pregnancy can cause serious harm to a developing baby. If rubella occurs during the first 8 to 12 weeks of pregnancy, there's a 50 to 80 percent chance that the baby will have such serious birth defects as mental retardation, blindness, hearing loss, and heart disease. Miscarriage or stillbirth are other possibilities. Almost a third of those babies whose mothers had rubella during pregnancy die within 4 months after birth. Termination of the pregnancy is often considered by expectant mothers who develop rubella. Vaccinations prompted by widespread awareness of this serious danger have dramatically lowered the number of babies affected by the disease while still in the uterus.

If you have a rash, low fever, swollen glands, and symptoms of the common cold, you could be suffering from rubella. A blood test will tell you whether you have had the disease—and whether the infection was recent. Immune globulin will lessen the effects of the virus if you decide to continue the pregnancy. Any woman who has never had rubella or been immunized against it—a group that includes about 10 to 15 percent of women of childbearing age in the United States—should receive the vaccine at least a few months before she tries to become pregnant.

Chickenpox. Chickenpox may play a role in preterm labor and birth defects. If you are pregnant and have never had chicken pox, you should get an injection of chickenpox immune globulin. If you contract the disease during late pregnancy and have it during labor, when it can be fatal to your baby, the doctor can give an injection of the globulin to the fetus through the placenta.

Mother's Use of DES

From about 1941 to 1971, many women with a history of miscarriage, premature delivery, moderate bleeding during pregnancy, or diabetes took a drug called diethlystilbestrol (DES). Years later, evidence showed that these women had increased their own risk for breast cancer and their daughters' risk for miscarriage, ectopic pregnancy, and premature delivery—among other problems. If your mother took DES when she was pregnant with you—and you should check all available medical records if you're not sure—be sure to discuss the situation with your gynecologist, preferably before becoming pregnant.

Sexually Transmitted Diseases

If you develop a sexually transmitted disease (STD) during pregnancy, you must get treatment immediately. Should you notice even the slightest evidence of an STD before conception, see your doctor right away, to prevent any risk to a future baby.

Syphilis. An untreated mother can pass syphilis on to a developing baby for up to 4 years after she contracted it. The baby may develop serious deformities and irreversible brain damage, and may even die from the disease. Fortunately syphilis responds well to penicillin and other antibiotics.

Chlamydia. Vaginal infection, pain during intercourse, and a general run­down feeling suggest infection with chlamydia. When present during pregnancy, chlamydia makes premature birth, miscarriage, or stillbirth 10 times more likely to occur. A baby delivered vaginally may contract the virus and develop eye disease (conjunctivitis) a few days later; doctors successfully treat this infection with antibiotic eye ointment. Erythromycin is the safest antibiotic treatment for chlamydia during pregnancy.

Gonorrhea. A woman with gonorrhea during pregnancy may go into labor before her due date; her baby may not grow properly and may develop conjunctivitis 2 to 7 days after birth. Penicillin or antibiotics will help prevent these problems.

Cytomegalovirus (CMV). In the United States, CMV is the most common viral infection of the uterus. Symptoms are similar to those of mononucleosis: sluggishness and general exhaustion. If contracted early in pregnancy, CMV can cause bleeding and liver disease in the mother, and may be a reason to opt for termination of the pregnancy. Symptoms of the virus in the baby may not appear immediately. A child with CMV might have hearing difficulties, learning disabilities, and a tendency to contract infections during the first 2 years of life.

Genital herpes. Babies born to mothers with active herpes lesions around the vagina can contract the disease directly from the sores. If laboratory tests confirm the infection, the mother can use acyclovir (Zovirax) to reduce the chance of fetal infection. Infection with herpes during pregnancy increases the risk of miscarriage and premature delivery. A child born to an infected mother may grow slowly or may even die. Doctors sometimes recommend cesarean section to keep the baby away from the sores. While there is no known cure for herpes, it can disappear for long periods of time. If you know you have had herpes, or think you might have, be sure to tell your doctor so that he or she can test you, especially toward the end of your pregnancy.

HIV infection and AIDS. Babies of women who are positive for human immunodeficiency virus (HIV), which causes AIDS, have a 25 to 30 percent chance of acquiring the infection during pregnancy. Extreme illness and early death are usually inevitable, although azidothymidine (AZT) has recently shown promise for protecting newborns against their mothers' HIV infection.

Nonviral Infections

Bacterial infections are easier to treat than viral infections.

Urinary tract infections. Two to 10 percent of pregnant women have urinary tract infections (UTIs). Most don't even realize it until the laboratory report comes in. One reason doctors routinely ask pregnant patients for urine specimens starting with the first appointment is their interest in treating a UTI as soon as possible.

Bladder infections (cystitis), the most common type of UTI, occur in a great many women (and in some men and children, too). The likelihood of developing cystitis increases during pregnancy and is especially strong in women who have had UTIs before. Changes in the immune system during pregnancy may be one reason for this increased risk. Also, the growing baby can cause the uterus to press against the bladder, preventing it from emptying completely and creating a breeding ground for bacteria (see chapter 10, “Putting an End to Urinary Tract Infections” for more information).

Infection can spread from the bladder up through the ureters to the kidney. Dangerous and painful in themselves, kidney infections can lead to premature birth. Doctors treat pregnant women with penicillin—usually ampicillin or amoxicillin—and the cephalosporins. Although the baby can't “catch” a UTI from its mother, a tendency for such infections may be hereditary.

Toxoplasmosis. Babies who contract this parasitic disease between conception and the twenty­fourth week tend to be born small and run the risk of developing liver disease, convulsions, blindness, brain abnormalities, and mental retardation. Since toxoplasmosis organisms live in raw or incompletely cooked meat and are carried in cat feces, pregnant women should eat only well­done meat and should avoid changing cat litter.

Hepatitis (inflammation of the liver). The risk to the baby is serious when the mother has chronic hepatitis B or C. Hepatitis A, which also requires treatment, has fewer dangerous side effects during pregnancy. To prevent neonatal hepatitis the doctor will give the baby hepatitis B immune globulin and vaccine immediately after birth. All male and female healthcare workers should get a vaccination before starting a child. The mother is also tested for hepatitis B during her pregnancy.

Troublemakers Part 2:
Conditions That Result from Pregnancy

Gestational diabetes

About 5 percent of pregnant women develop diabetes for the first time during pregnancy. Gestational diabetes poses the same risks to the baby as chronic diabetes, but usually disappears after the baby is born. The mother's risk of having diabetes in a future pregnancy or later in life, however, may go up.

You're more likely to get gestational diabetes if you had the condition before; if an earlier pregnancy ended in stillbirth; if a family member has diabetes; if you suffer from recurrent vaginal or urinary tract infections; or if you're overweight or over 25 years of age. When risk factors are present, your doctor will give you oral glucose tolerance tests earlier than the usual 24 to 28 weeks of gestation.

Chronic vomiting

Nausea and vomiting, especially during the first 3 months, are probably the most universally known signs of pregnancy. In some cases, the vomiting is frequent enough to produce weakness, dehydration, and eventual damage to the kidneys and liver. Stress and fear worsen the situation. If vomiting is serious, a woman may need hospitalization so that she can receive nutrients intravenously.

How much vomiting is too much? If you throw up more than 3 or 4 times a day, are unable to hold any food down, lose weight, faint, run a fever, or urinate less than usual, call your doctor immediately. Since vomiting can destroy tooth enamel, it's important to keep your teeth and gums very clean and see a dentist for frequent cleaning.

Bleeding

Although between 25 and 50 percent of pregnant women experience some spotting, especially at the beginning, any bleeding during pregnancy is cause for concern. The doctor may tell you to go to bed and stay there until 48 hours after the bleeding has stopped. Very heavy bleeding (hemorrhaging) requires an emergency trip to the hospital. During the second and third trimesters, any bleeding is usually caused by the placenta (see the following pages). If you experience vaginal bleeding, call your doctor right away. Describe the color and amount of blood, any associated symptoms, the type of pain (if any), and what you were doing when you started to bleed.

Excess­or Too Little­Amniotic Fluid

When there is too much fluid in the amniotic sac that surrounds the baby inside the uterus, the mother has hydramnios. The condition can develop suddenly or gradually. The extra fluid can prevent normal chest expansion, thus causing shortness of breath. Premature labor and delivery may result as well. The doctor may perform amniocentesis (withdrawing amniotic fluid with a long needle) one or more times to remove some of the excess fluid. Hospitalization may be necessary.

Oligohydramnios, an equally serious situation, occurs when there is too little amniotic fluid. To prevent compression of the umbilical cord and other problems, the doctor may deliver the baby early.

Intrauterine Growth Retardation (IUGR)

When a newborn measures less than 18 inches or weighs less than 5 pounds, it has IUGR. Small babies are weaker than larger ones and require more medical help. If your baby doesn't seem to be growing enough, the physician may prescribe bed rest to increase its oxygen supply and nutrition. Remember, though, that smaller mothers tend to have smaller babies.

Premature Rupture of Membranes (PROM)

Many conditions of pregnancy can cause the membranes to break too early, sometimes necessitating a quick trip to the hospital, followed by delivery. (For more information, see chapter 26, “What to Expect during Labor and Delivery.”)

Rh Incompatibility

If the father's and the baby's blood contains a component called Rh factor, but the mother's does not, the baby can develop Rh disease. (In the United States, only 15 percent of whites and 5 percent of blacks are Rh negative.) Problems occur, usually in a second pregnancy or later, if a few cells of fetal blood leak into the mother's, typically at the time of delivery. The mother's Rh­negative system treats these cells as foreign objects, producing antibodies against them. If the baby is still in the uterus—and in future pregnancies—antibodies can enter and destroy some of the baby's red blood cells, leading to anemia, heart failure, and death.

The doctor may decide to deliver early if amniocentesis—evaluation of a sample of the amniotic fluid—reveals too much bilirubin, an orange­yellow pigment formed when blood cells break down. A substantial amount of bilirubin suggests that Rh antibodies from the mother have destroyed the fetal cells, and that there is an Rh incompatibility problem.

A drug called RH _o(D) immune globulin (Gamulin Rh, RhoGAM, others) prevents Rh antibodies from forming. It is given to Rh­negative women within 72 hours of delivering an Rh­positive baby (or having a miscarriage, abortion or amniocentesis), to protect future pregnancies from Rh incompatibility. Some doctors also inject RH _o(D) immune globulin at 28 to 32 weeks of gestation. The fetus or newborn can also receive blood transfusions directly, if necessary.

Placenta Previa

In about 1 out of 200 pregnancies, the placenta develops abnormally low in the uterus. Because the walls of the lower third of the uterus are thinner than those of the upper uterus, the mother's blood supply is smaller there. If this situation develops you may notice spotting during the last trimester, usually after 30 weeks. In addition, the lower uterine walls may cover some or all of the cervix. Since this location would make a vaginal birth difficult or impossible, and the fetus needs a healthy blood supply, the doctor usually orders bed rest to prevent excessive bleeding. If the condition is discovered during the first 20 weeks, the placenta may migrate out of the way. Sexual intercourse is inadvisable. Ninety percent of the time, in early cases, the situation corrects itself; and the vast majority of women who develop this condition deliver perfectly normal babies with few complications.

PLACENTA PREVIA (“PLACENTA FIRST”)

When the placenta blocks normal access to the birth canal at the end of a pregnancy, cesarean delivery is usually a must. However, placenta previa discovered early in the pregnancy (during the first 20 weeks) usually corrects itself. If your doctor discovers this problem, the most likely prescription will be bed rest.

Placenta previa can be total, partial, or marginal. Risk factors include previous placenta previa, a previous cesarean section, scar tissue in the uterus, 5 or more pregnancies, and being more than 35 years old. Possible causes range from unusual fetal position or a multiple pregnancy to previous uterine surgery, advanced age, or congenital abnormalities.

The mother may suspect something is wrong when she experiences severe bleeding, which can lead to anemia and low blood volume. Or she may see a discharge of bright­red blood but have no pain or cramping. Even if placenta previa occurs without symptoms, the doctor may find it on a routine ultrasound scan or one performed for other reasons.

After delivery of the baby in placenta previa, the uterus may be unable to contract tightly enough to shut off the blood vessels shorn away when the placenta detached from the uterine wall. To prevent hemorrhage and the possibility of subsequent shock, the mother may need intravenous fluids and blood infusions as well as medication that will encourage the uterus to contract. Even if she does not hemorrhage, she may have to take oral or intravenous antibiotics after delivery of a placenta previa to prevent uterine infection.

IF THE PLACENTA TEARS AWAY

When all or part of the placenta tears loose from the wall of uterus, the medical term for the situation is “placental abruption” and bleeding is bound to occur. If hemorrhaging is relatively minor, the doctor may order bed rest in hopes that the rupture will heal. Heavy bleeding, however, can be life-threatening for both you and the baby, and calls for immediate delivery, usually by cesarean.

Placental Abruption

In this rare emergency, the placenta shears partly or entirely loose from the uterus before delivery. About half the time, this occurs after the 36th week, when immediate cesarean section is safe. Symptoms include vaginal bleeding after the 20th week, nausea and vomiting, and severe abdominal pain. Abruption occurs more often in women who have had many previous pregnancies, particularly those with high blood pressure and preeclampsia.

Multiple Births

Twins, triplets, and more are considered a “complication” of pregnancy because multiple fetuses have greater nutritional needs than a single baby and place additional strain on the mother's body. Sleeping, eating, and remaining physically comfortable may pose challenges sooner than in a one­baby pregnancy. The risks of high blood pressure, hydramnios, and postpartum hemorrhage are also higher. About half of multiple births are premature.

Doctors often advise bed rest or a drastic reduction of activity and stress, sometimes for most of the pregnancy. Cesarean section is usually recommended for triplets and quadruplets. Preeclampsia is 3 to 5 times more common with twins than with solo babies; it occurs in 20 to 30 percent of all twin pregnancies. If you are having more than one baby, contact one of the advocacy groups for parents of “multiples,” such as the International Twins Association in Denver and the Triplet Connection in Stockton, California.

Postmaturity

About 10 percent of pregnancies extend beyond their projected due dates. Any pregnancy that's still going strong 2 or more weeks after that date is considered “postmature,” especially if the mother's or baby's health seems in jeopardy. After 40 weeks' gestation, the amount of oxygen and nutrients reaching the baby begins to decline. Furthermore, if a baby grows too large, there's less chance of a normal vaginal birth. An overterm baby is also more likely to undergo fetal distress during labor, especially if the mother is 35 or older and this is her first child.

Many doctors prefer to induce labor 2 weeks beyond the due date; others wait. Ultrasound scans and electronic fetal monitoring help determine whether the fetus is healthy and can wait for delivery. The tests may be done biweekly.

Tests and Procedures

If you have a complicated pregnancy, your doctor is likely to recommend quite a few of the tests and procedures described in chapter 24, “Prenatal Tests to Consider.” Amniocentesis is often performed at 34 to 39 weeks to evaluate fetal maturity (and the feasibility of early delivery) in cases of high blood pressure, Rh incompatibility, diabetes, and postmaturity.

Other tests commonly given to women with high­risk pregnancies are biophysical profiles (to evaluate fetal heart rate and activity) and sonography (ultrasound). Women with diabetes are taught to test themselves. Home uterine monitoring for conditions such as high blood pressure and premature labor allows many women to remain safely at home despite difficulties during pregnancy.

Medications During Pregnancy

The U.S. Food and Drug Administration has categorized all federally approved medications according to their known or suspected safety—or lack of safety—during pregnancy. We still don't know much about the effects of many drugs on the pregnant woman and her baby, partly because doctors have been extremely reluctant to prescribe almost any medication since the thalidomide scare of the 1960s and the DES discoveries of the 1980s. Your doctor will insist on overseeing any and all drugs you take during pregnancy—including aspirin, which may seem harmless, but can, in fact, affect the baby.

Antibiotics

Some infections, such as sexually transmitted diseases and urinary tract infections, are serious enough to require medication during pregnancy, despite the potential risks. Don't take anything without your doctor's permission and supervision, and be sure to tell him or her about any illness or symptoms you may have.

Drugs to Delay Labor

These drugs are given either orally or intravenously to postpone labor that starts too soon—usually at 20 weeks or later. The goal is to keep the pregnancy on course long enough to allow the baby's lungs to mature to the point that it can breathe on its own.

Tocolytic medications, such as indomethacin (Indocin), ritrodine (Yutopar), terbutaline (Brethaire, Bricanyl), and magnesium sulfate, act in different ways but can have similar effect on labor. All of them have potential side effects, such as palpitations, nausea, and nasal congestion.

Drugs to Induce Labor

When labor has begun but then stalls, the physician may give you an injection to “jump­start” the uterine muscles. The drugs used include Pitocin and Syntocinon. Doctors sometimes prescribe Prostaglandin gel to encourage softening and thinning of the cervical opening in preparation for delivery.

Reassurance

Despite complications, most “high­risk” pregnancies end with the birth of a healthy baby. Doctors already have the means to control most threats, and they're learning more all the time.

Unfortunately, newspapers and popular magazines often report new treatments before they've really been proven. The reports are usually brief and sound conclusive. In fact, research may be flawed or need to be repeated many times before its results will be accepted by most physicians. Still, whenever you read about a condition or treatment that could affect your pregnancy, don't hesitate to discuss your concerns with your doctor. Visit often, call when you have questions, and follow his or her advice, even if it's hard. Remember, the best way to protect your baby is to take good care of yourself.