American Medical Association Family Medical Guide - American Medical Association [293]
Because high blood pressure reduces the efficiency of the placenta (which provides the fetus with oxygen and nutrients), some doctors think that high blood pressure may retard the growth of the fetus and may lead to preterm delivery. High blood pressure during pregnancy can also damage the woman’s kidneys, brain, eyes, and liver.
In some cases, preeclampsia leads to an even more serious condition called eclampsia. In eclampsia, blood pressure gets so high that it decreases oxygen to the pregnant woman’s brain and causes seizures, which can be life-threatening to her and to the fetus. Seizures have been linked to stroke, the most common cause of maternal death from eclampsia.
Symptoms
Because the symptoms of preeclampsia are not noticeable at first, make sure you go to all of your prenatal checkups so that preeclampsia can be diagnosed early and treated. The symptoms of severe preeclampsia include headaches, blurred vision, intolerance to bright light, upper abdominal pain, nausea and vomiting, and bloating.
Treatment
If you have preeclampsia, your doctor will recommend that you get lots of rest and reduce your salt intake to help lower your blood pressure. He or she may prescribe a medication to control your blood pressure. The doctor will order ultrasound scans regularly to monitor the fetus’s growth and to watch for a buildup of amniotic fluid. If you have symptoms of severe preeclampsia or of eclampsia, you will be admitted to a hospital immediately and will be given medication to lower your blood pressure and remove excess fluid from your body. Your doctor may recommend immediate delivery by inducing labor (see page 533) or performing a cesarean delivery (see page 534).
Placenta Previa and Placental Abruption
Normally, the placenta is attached to the top portion of the uterus. Any part of the placenta that is near the cervix (the opening into the uterus) is poorly supported and vulnerable to damage. In placenta previa, the placenta develops low in the uterus, either partially or completely covering the cervix and blocking the entrance to the vagina. The weight of the fetus puts pressure on the part of the placenta that covers the cervix, sometimes causing bleeding if part of the placenta detaches from the wall of the uterus. Placenta previa occurs in about 1 in 200 pregnancies after the 28th week.
The cause of placenta previa is unknown. It occurs more frequently in women who have given birth to several children and in pregnancies with multiple fetuses (see page 525). In some cases, the placenta is low in the uterus early in pregnancy but then moves up the wall of the uterus to a more normal position as the pregnancy progresses, where it usually does not interfere with delivery.
If the placenta ruptures or tears, causing heavy bleeding, it can cut off the blood supply to the fetus. In placental abruption, a placenta that is positioned normally in the uterus separates prematurely from the uterine wall. Placental abruption is more common in women who have high blood pressure (see page 520). Placental abruption may be linked to a deficiency of the B vitamin folic acid.
Symptoms
Placenta previa may cause no symptoms. If the placenta becomes partly detached from the uterus, the woman will have sporadic bleeding but usually no pain. Placental abruption may cause some pain along with the bleeding. However, in some cases, placental abruption causes no bleeding because the blood is trapped between the wall of the uterus and the placenta. This collection of blood can trigger preterm labor (see page 529).
Diagnosis and Treatment
If the placenta is only partially