American Medical Association Family Medical Guide - American Medical Association [294]
If you have vaginal bleeding, call your doctor immediately. (Don’t try to stop the bleeding by putting in a tampon.) If the bleeding is light or stops on its own and the fetus is not in any danger, your doctor will probably monitor your condition with ultrasound. If the bleeding is severe, you may need to have a blood transfusion, and the baby will be delivered as soon as possible by cesarean (see page 534). Severe bleeding is dangerous but rarely fatal to the pregnant woman, but it can be fatal to the fetus.
Placenta previa
The normal placement of the placenta is near the top of the uterus. In placenta previa, the placenta is attached at the bottom of the uterus, where it can partially or completely cover the cervix. If the placenta reaches to the edge of the cervix but does not cover it, the condition is called marginal placenta previa (left). In partial placenta previa (center), the placenta blocks part of the cervix. In complete placenta previa (right), the placenta covers the entire cervix.
Premature Rupture of the Membranes
When labor begins, the membranes surrounding the fetus rupture, releasing amniotic fluid (often referred to as the water breaking). The amniotic fluid may leak out slowly through the vagina or in a sudden rush. Occasionally, the membranes rupture before labor has begun. The main risks of premature rupture of the membranes containing the amniotic fluid are infection and preterm labor (see next page).
Diagnosis and Treatment
If your membranes have ruptured prematurely, you probably will be admitted to the hospital. Your doctor will collect any remaining fluid and perform amniocentesis (see page 510) to determine if the fetus’s lungs are developed enough for delivery. Sometimes a small tear in the membranes surrounding the fetus heals and the pregnancy can continue. Because there is a risk of infection, you may have to stay in the hospital so your condition and the health of the fetus can be monitored carefully. If the fetus is mature enough (usually after the 36th week) or if there is sign of an infection, labor will be induced (see page 533).
Chorioamnionitis
Chorioamnionitis is infection of the chorion and amnion membranes of the placenta and the amniotic fluid that surrounds the fetus. The infection, caused by bacteria that enter the uterus from the vagina, usually occurs at the end of pregnancy when more than 24 hours elapse between the time the membranes rupture and delivery. In rare cases, the infection develops earlier, before the 37th week of pregnancy, and causes preterm labor (see next page). The symptoms of chorioamnionitis include tenderness in the uterus and a fever. The fetus may have signs of infection such as an unusually high heart rate.
Treatment
Chorioamnionitis is treated with antibiotics given intravenously (through a vein) to the mother and immediate delivery (because the antibiotics given to the mother don’t reach the fetus). If the baby is born with a severe infection, he or she is given antibiotics intravenously to prevent or treat other, more serious infections, such as pneumonia or meningitis.
Preterm Labor
Labor is considered to be preterm (or premature) if it occurs between about the 24th and 36th weeks of pregnancy. About 5 percent of pregnancies result in preterm labor. Severe preeclampsia or eclampsia (see page 526) account for about a third of all cases of preterm delivery. High blood pressure (see page 520), placenta previa and placental abruption (see page 527), vaginal bleeding (see page 523), and other factors, such as cigarette smoking and drug abuse, account for some cases of preterm labor.
The earlier in a pregnancy a baby is born, the lower his or her chances of survival. Preterm infants who survive run the risk of having respiratory distress syndrome (see page 381), neonatal jaundice (see