For many people, hypertension, also known as high blood pressure, is a chronic problem, but some women develop the condition temporarily, during the course of pregnancy. According to the National Heart Lung and Blood Institute, 6 to 8 percent of pregnant women develop pregnancy induced hypertension.
Definition
Pregnancy-induced hypertension, also called PIH or gestational hypertension, is defined as high blood pressure that develops after the 20th week of pregnancy. Before that point, any diagnosed hypertension is presumed to be chronic. Since normal blood pressure falls under 140/90, anything over either of these numbers will result in a PIH diagnosis. If the doctor also finds protein in the pregnant woman's urine, this will typically result in a diagnosis of preeclampsia.
Effects
Mild PIH doesn't generally cause any symptoms or complications for either mother or baby, especially when it occurs late in the pregnancy. PIH that develops earlier in the pregnancy or that results in very high blood pressure carries more risk for the mother and baby. PIH results in an increased risk of developing preeclampsia and a higher risk that the mother will need an induced labor or C-section. Other potential complications include preterm labor and birth, fetal growth restriction, stillbirth, seizures in the mother, and the early detachment of the placenta from the uterine wall.
Treatment
For mild PIH, the doctor will monitor the pregnant woman regularly to make sure her blood pressure doesn't rise further and she doesn't start to have signs of preeclampsia. If her blood pressure continues to rise, she may require medication to lower it, or the doctor may recommend delivering the baby early by induction or C-section. At-home care may include bed rest for the pregnant woman.
Monitoring
Blood pressure during pregnancy is typically monitored using a standard blood pressure cuff during each prenatal visit. Also, a urinalysis performed at each visit allows the doctor to watch for signs of protein in the urine. If hypertension is diagnosed, a more sensitive 24-hour urine test can be administered to look for protein. Blood tests, ultrasounds, biophysical profile tests, nonstress tests and a fetal Doppler may also be used to assess the health of the baby.
Causes and Risks
There are no known causes for PIH, but some things have been determined to raise the risk of developing the condition. Women who have had gestational hypertension in a previous pregnancy are more likely to develop PIH. Other risk factors for PIH include obesity, being under 20 or over 40 years of age, and carrying more than one baby. Certain diseases may also increase the risk, such as diabetes, kidney disease and lupus.
