Pre-eclampsia, or hypertension during pregnancy, may appear as early as the 20th week of pregnancy and occasionally as late as one week after delivery. Occurring in about 5%–8% of all pregnancies, it’s most common among women experiencing their first pregnancy and women who already have high blood pressure. Most cases of hypertension that develop during pregnancy disappear soon after the child’s birth. Hypertension that persists is called pregnancy-induced hypertension.

The cause of pre-eclampsia is unknown. Signs of pre-eclampsia include swelling of the hands and face, blood-clotting abnormalities, and protein in the urine. For most women, pre-eclampsia never proceeds beyond the mild stage. For some women, though, the disease develops rapidly, moving from mild to severe in a matter of weeks or sometimes days. Doctors usually recommend bed rest. But if the problem remains or worsens, hospitalization and antihypertensive medications are often necessary to prevent pre-eclampsia from progressing to eclampsia, a serious medical condition. Eclampsia can cause dangerously high blood pressure, seizure, coma, and even the death of the mother, the fetus, or both. Since eclampsia frequently disappears once the baby is born, doctors often induce labor. They may also prescribe anticonvulsant medications. If the woman still has hypertension after giving birth, she may need medication. Little is known about the effects of antihypertensive agents in breast milk, however, so breast-fed  infants must be closely monitored.