Pregnancy complications are problems that occur only during pregnancy. They may affect the woman, the fetus, or both and may occur at different times during the pregnancy. For example, complications such as a mislocated placenta (placenta previa) or premature detachment of the placenta from the uterus (placental abruption) can cause bleeding from the vagina during the last 3 months of pregnancy. Women who bleed at this time are at risk of losing the baby or of bleeding excessively (hemorrhaging) or dying during labor and delivery. However, most pregnancy complications can be effectively treated.
Ectopic Pregnancy: A Mislocated Pregnancy
Normally, an egg is fertilized in the fallopian tube and becomes implanted in the uterus. However, if the tube is narrowed or blocked, the egg may move slowly or become stuck. The fertilized egg may never reach the uterus, resulting in an ectopic pregnancy. Ectopic pregnancies usually develop in one of the fallopian tubes (as a tubal pregnancy) but may develop in other locations. A fetus in an ectopic pregnancy cannot survive.
One of 100 to 200 pregnancies is an ectopic pregnancy. Risk factors for an ectopic pregnancy include having had a disorder of the fallopian tubes, pelvic inflammatory disease, a previous ectopic pregnancy, exposure to diethylstilbestrol as a fetus, or a tubal ligation (a sterilization procedure) that was unsuccessful or has been surgically reversed.
Symptoms include unexpected vaginal bleeding and cramping. The fetus may grow enough to rupture the structure containing it. If the fallopian tube ruptures (typically after about 6 to 8 weeks), a woman usually feels severe pain in the lower abdomen and may faint. If the tube ruptures later (after about 12 to 16 weeks), the risk of death for the woman is increased, because the fetus and placenta are larger and more blood is lost.
If a woman is unsure she is pregnant, a pregnancy test is performed. If she is pregnant, ultrasonography is performed to determine the location of the fetus. If the uterus is empty, doctors may suspect an ectopic pregnancy. If ultrasonography shows the fetus in a location other than the uterus, the diagnosis is confirmed. Doctors may use a viewing tube called a laparoscope, inserted through a small incision just below the navel, to view the ectopic pregnancy directly.
An ectopic pregnancy must be ended as soon as possible to save the life of the woman. In most women, the fetus and placenta in an ectopic pregnancy must be removed surgically, usually with a laparoscope but sometimes through an incision in the abdomen (in a procedure called laparotomy). Rarely, the uterus is so damaged that a hysterectomy is required. Sometimes, the drug methotrexate, usually given in a single injection, can be used instead of surgery. The drug causes the ectopic pregnancy to shrink and disappear. Occasionally, surgery is needed in addition to methotrexate.
Some problems that result from hormonal changes during pregnancy cause only minor, transient symptoms in pregnant women. For example, the normal hormonal effects of pregnancy can slow the movement of bile through the bile ducts. Cholestasis of pregnancy may result. The most obvious symptom is itching all over the body (usually in the last few months of pregnancy). No rash develops. If itching is intense, cholestyramine may be given. The disorder usually resolves after delivery but tends to recur in subsequent pregnancies.
Hyperemesis gravidarum is extremely severe nausea and excessive vomiting during pregnancy. Hyperemesis gravidarum differs from ordinary morning sickness. If women vomit often and have nausea to such an extent that they lose weight and become dehydrated, they have hyperemesis gravidarum. If women vomit occasionally but gain weight and are not dehydrated, they do not have hyperemesis gravidarum. The cause of hyperemesis gravidarum is unknown.
Because hyperemesis gravidarum can be life threatening to pregnant women and the fetus, women who have it are hospitalized. An intravenous line is inserted into a vein to give fluids, sugar (glucose), electrolytes, and occasionally vitamins. Women who have this complication are not allowed to eat or drink anything for at least 24 hours. Sedatives, antiemetics, and other drugs are given as needed. After women are rehydrated and vomiting has subsided, they can begin eating frequent, small portions of bland foods. The size of the portions is increased if they can tolerate more food. Usually, vomiting stops within a few days. If symptoms recur, the treatment is repeated. Rarely, if weight loss continues and symptoms persist despite treatment, women are fed via a tube passed through the nose and down the throat to the small intestine for as long as necessary.
About 5% of pregnant women develop preeclampsia (toxemia of pregnancy). In this complication, an increase in blood pressure is accompanied by protein in the urine (proteinuria). Preeclampsia usually develops between the 20th week of pregnancy and the end of the first week after delivery. The cause of preeclampsia is unknown. But it is more common among women who are pregnant for the first time, who are carrying two or more fetuses, who have had preeclampsia in a previous pregnancy, who already have high blood pressure or a blood vessel disorder, or who have sickle cell disease. It is also more common among girls aged 15 and younger and among women aged 35 and older.
A variation of severe preeclampsia, called the HELLP syndrome, occurs in some women. It consists of the following:
• hemolysis (the breakdown of red blood cells)
• elevated levels of liver enzymes, indicating liver damage
• low platelet count, making blood less able to clot and increasing the risk of bleeding during and after labor.
In 1 of 200 women who have preeclampsia, blood pressure becomes high enough to cause seizures; this condition is called eclampsia. One fourth of the cases of eclampsia occur after delivery, usually in the first 2 to 4 days. If not treated promptly, eclampsia may be fatal.
Preeclampsia may lead to premature detachment of the placenta from the uterus (placental abruption). Babies of women who have preeclampsia are 4 or 5 times more likely to have problems soon after birth than babies of women who do not have this complication. Babies may be small because the placenta malfunctions or because they are born prematurely.
If mild preeclampsia develops early in the pregnancy, bed rest at home may be sufficient, but such women should see their doctor frequently. If preeclampsia worsens, women are usually hospitalized. There, they are kept in bed and monitored closely until the fetus is mature enough to be delivered safely. Antihypertensives may be needed. A few hours before delivery, magnesium sulfate may be given intravenously to reduce the risk of seizures. If preeclampsia develops near the due date, labor is usually induced and the baby is delivered.
If preeclampsia is severe, the baby may be delivered by cesarean section, which is the quickest way, unless the cervix is already opened (dilated) enough for a prompt vaginal delivery. A prompt delivery reduces the risk of complications for women and the fetus. If blood pressure is high, drugs to lower blood pressure, such as hydralazine or labetalol, may be given intravenously before delivery is attempted. Treatment of the HELLP syndrome is usually the same as that of severe preeclampsia.
After delivery, women who have had preeclampsia or eclampsia are closely monitored for 2 to 4 days because they are at increased risk of seizures. As their condition gradually improves, they are encouraged to walk. They may remain in the hospital for a few days, depending on the severity of the preeclampsia and its complications. After returning home, these women may need to take drugs to lower blood pressure. Typically, they have a checkup at least every 2 weeks for the first few months after delivery. Their blood pressure may remain high for 6 to 8 weeks. If it remains high longer, the cause may be unrelated to preeclampsia.
About 1 to 3% of pregnant women develop diabetes during pregnancy. This disorder is called gestational diabetes. Unrecognized and untreated, gestational diabetes can increase the risk of health problems for pregnant women and the fetus and the risk of death for the fetus. Gestational diabetes is more common among obese women and among certain ethnic groups, particularly Native Americans, Pacific Islanders, and women of Mexican, Indian, and Asian descent.
Most women with gestational diabetes develop it because they cannot produce enough insulin as the need for insulin increases late in the pregnancy. More insulin is needed to control the increasing level of sugar (glucose) in the blood. Some women may have had diabetes before becoming pregnant, but it was not recognized until they became pregnant.
Some doctors routinely screen all pregnant women for gestational diabetes. Other doctors screen only women who have risk factors for diabetes, such as obesity and certain ethnic backgrounds. A blood test is used to measure the blood sugar level. Women who have gestational diabetes are usually taught to measure their blood sugar levels with a home blood sugar monitoring device.
Treatment consists of eliminating high-sugar foods from the diet, eating to avoid excess weight gain during the pregnancy, and, if the blood sugar level is high, taking insulin. After delivery, gestational diabetes usually disappears. However, many women who have gestational diabetes develop type 2 diabetes as they become older.
Rh incompatibility occurs when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood, inherited from a father who has Rh-positive blood. The Rh factor is a molecule that occurs on the surface of red blood cells of some people. Blood is Rh-positive if red blood cells have the Rh factor and Rh-negative if they do not. Problems can occur if the fetus's Rh-positive blood enters the woman's bloodstream. The woman's immune system may recognize the fetus's red blood cells as foreign and produce antibodies, called Rh antibodies, to destroy the fetus's red blood cells. The production of these antibodies is called Rh sensitization.
During a first pregnancy, Rh sensitization is unlikely, because no significant amount of the fetus's blood is likely to enter the woman's bloodstream until delivery. So the fetus or newborn rarely has problems. However, once a woman is sensitized, problems are more likely with each subsequent pregnancy in which the fetus's blood is Rh-positive. In each pregnancy, the woman produces Rh antibodies earlier and in larger amounts.
If Rh antibodies cross the placenta to the fetus, they may destroy some of the fetus's red blood cells. If red blood cells are destroyed faster than the fetus can produce new ones, the fetus can develop anemia. Such destruction is called hemolytic disease of the fetus (erythroblastosis fetalis) or of the newborn (erythroblastosis neonatorum). In severe cases, the fetus may die.
At the first visit to a doctor during a pregnancy, women are screened to determine whether they have Rh-positive or Rh-negative blood. If they have Rh-negative blood, their blood is checked for Rh antibodies and the father's blood type is determined. If he has Rh-positive blood, Rh sensitization is a risk. In such cases, the blood of pregnant women is checked for Rh antibodies periodically during the pregnancy. The pregnancy can proceed as usual as long as no antibodies are detected.
If antibodies are detected, steps may be taken to protect the fetus, depending on how high the antibody level is. If the level becomes too high, amniocentesis may be performed. In this procedure, a needle is inserted through the skin to withdraw fluid from the amniotic sac. The level of bilirubin (a yellow pigment resulting from the normal breakdown of red blood cells) is measured in the fluid sample. If this level is too high, the fetus is given a blood transfusion. Usually, additional transfusions are given until the fetus is mature enough to be safely delivered. Then labor is induced. The baby may need additional transfusions after birth. Sometimes no transfusions are needed until after birth.
As a precaution, women who have Rh-negative blood are given an injection of Rh antibodies at 28 weeks of pregnancy and within 72 hours after delivery of a baby who has Rh-positive blood, even after a miscarriage or an abortion. The antibodies given are called Rh0(D) immune globulin. This treatment destroys any red blood cells from the baby that may have entered the bloodstream of the women. Thus, there are no red blood cells from the baby to trigger the production of antibodies by these women, and subsequent pregnancies are usually not endangered.
Fatty Liver of Pregnancy:
This rare disorder occurs toward the end of pregnancy. The cause is unknown. Symptoms include nausea, vomiting, abdominal discomfort, and jaundice. The disorder may rapidly worsen, and liver failure may develop. Diagnosis is based on results of liver function tests and may be confirmed by a liver biopsy. The doctor may advise immediate termination of the pregnancy. The risk of death for pregnant women and the fetus is high, but those who survive recover completely. Usually, the disorder does not recur in subsequent pregnancies.
The heart's walls may be damaged late in pregnancy or after delivery, causing peripartum cardiomyopathy. The cause is unknown. Peripartum cardiomyopathy tends to occur in women who have had several pregnancies, who are older, who are carrying twins, or who have preeclampsia. In some women, heart function does not return to normal after pregnancy. They may develop peripartum cardiomyopathy in subsequent pregnancies. These women should not become pregnant again. Peripartum cardiomyopathy can result in heart failure, which is treated.
Problems With Amniotic Fluid:
Too much amniotic fluid (polyhydramnios) in the membranes containing the fetus (amniotic sac) stretches the uterus and puts pressure on the diaphragm of pregnant women. This complication can lead to severe breathing problems for the women or to preterm labor.
Too much fluid tends to accumulate when pregnant women have diabetes, are carrying more than one fetus (multiple pregnancy), or produce Rh antibodies to the fetus's blood. Another cause is birth defects in the fetus, especially a blocked esophagus or defects of the brain and spinal cord (such as spina bifida). About half the time, the cause is unknown.
Too little amniotic fluid (oligohydramnios) can also cause problems. If the amount of fluid is greatly reduced, the fetus's lungs may be immature and the fetus may be compressed, resulting in deformities; this combination of conditions is called Potter's syndrome.
Too little amniotic fluid tends to develop when the fetus has birth defects in the urinary tract, has not grown as much as expected, or dies. Other causes include the use of angiotensin-converting enzyme (ACE) inhibitors, such as enalapril or captopril, in the 2nd and 3rd trimesters. These drugs are given during pregnancy only when they must be used to treat severe heart failure or high blood pressure. Taking nonsteroidal anti-inflammatory drugs (NSAIDs) late in pregnancy can also reduce the amount of amniotic fluid.
Placenta previa is implantation of the placenta over or near the cervix, in the lower rather than the upper part of the uterus. The placenta may completely or partially cover the opening of the cervix. Placenta previa occurs in 1 of 200 deliveries, usually in women who have had more than one pregnancy or who have structural abnormalities of the uterus, such as fibroids.
Placenta previa can cause painless bleeding from the vagina that suddenly begins late in pregnancy. The blood may be bright red. Bleeding may become profuse, endangering the life of the woman and the fetus.
Ultrasonography helps doctors identify placenta previa and distinguish it from a placenta that has detached prematurely (placental abruption).
When bleeding is profuse, women may be hospitalized until delivery, especially if the placenta is located over the cervix. Women who bleed profusely may need repeated blood transfusions. When bleeding is slight and delivery is not imminent, doctors typically advise bed rest in the hospital. If the bleeding stops, women are usually encouraged to walk. If bleeding does not recur, they are usually sent home, provided that they can return to the hospital easily. A cesarean section is almost always performed before labor begins. If women with placenta previa go into labor, the placenta tends to become detached very early, depriving the baby of its oxygen supply. The lack of oxygen may result in brain damage or other problems in the baby.
Placental Abruption (Abruptio Placentae):
Placental abruption is the premature detachment of a normally positioned placenta from the wall of the uterus. The placenta may detach incompletely (sometimes just 10 to 20%) or completely. The cause is unknown. Detachment of the placenta occurs in 0.4 to 3.5% of all deliveries. This complication is more common among women who have high blood pressure (including preeclampsia) and among women who use cocaine.
The uterus bleeds from the site where the placenta was attached. The blood may pass through the cervix and out the vagina as an external hemorrhage, or it may be trapped behind the placenta as a concealed hemorrhage. Symptoms depend on the degree of detachment and the amount of blood lost (which may be massive). Symptoms may include sudden continuous or crampy abdominal pain, tenderness when the abdomen is pressed, and shock. Premature detachment of the placenta can lead to widespread clotting inside the blood vessels (disseminated intravascular coagulation), kidney failure, and bleeding into the walls of the uterus, especially in pregnant women who also have preeclampsia. When the placenta detaches, the supply of oxygen and nutrients to the fetus may be reduced.