Hypertension is defined by the American Congress of Obstetricians and Gynecologists as blood pressure readings greater than 140/90 mm Hg. According to the National Heart Lung and Blood Institute, hypertension occurs in 6 to 8 percent of all pregnancies in the U.S., 70 percent of which are first-time pregnancies. Different hypertensive conditions may occur during pregnancy. Chronic hypertension presents before the 20th week of pregnancy, or persists 12 weeks after delivery. Gestational hypertension develops after the 20th week of pregnancy and disappears soon after delivery. Preeclampsia also occurs after the 20th week of pregnancy, but is accompanied by protein in the urine, and can cause serious consequences for both mother and baby if not properly managed.
Placental Abruption
Hypertension during pregnancy increases the risk for placental abruption, which the March of Dimes describes as separation of the placenta from the uterus prior to onset of labor. Severe cases of abruption can result in strong contractions and heavy bleeding, and may even cause death of both mother and baby. Placental abruption that occurs prior to the 37th week of pregnancy also leads to preterm delivery.
Low Birth Weight
Hypertension can cause less blood flow to the placenta, resulting in decreased delivery of oxygen and nutrients to the fetus. This can slow down the growth of the fetus and lead to low birth weight.
Preterm Delivery
Some severe cases of hypertension during pregnancy may necessitate delivery of the baby. If this occurs prior to the 37th week of pregnancy, it results in preterm birth. Preterm and low birth weight babies are at increased risk of developing complications, such as infections and breathing difficulties, during and after delivery.
Severe Preeclampsia
Severe preeclampsia can damage different organ systems in the mother, including the liver, heart, brain and kidneys. It may also progress to a life-threatening condition called eclampsia, wherein the mother suffers seizures, and even coma and death.
