Women who are considering pregnancy or who are pregnant may have certain underlying medical problems. Some of these preexisting medical problems can lead to complications during pregnancy. One of the most common medical problems that women have before they become pregnant is chronic hypertension, also known as chronic high blood pressure.
High blood pressure is present in about 5 percent of all women of childbearing age. Some women are able to control their blood pressure with exercise, weight loss, limiting alcohol use, reducing sodium intake and following specific diets that are abundant with fruits and vegetables, low in fat dairy products and high in fiber.
Some women may be on blood pressure lowing medications before they become pregnant. Usually these are started to keep your systolic blood pressure less than 140 (top number) and to keep the diastolic blood pressure less than 90 (bottom number). Medications from almost every antihypertensive drug class have been prescribed during pregnancy but the data on safety are incomplete and limited to a few medications.
Hypertension that occurs during pregnancy complicates up to 10 percent of all pregnancies. There can be very serious complications to you or your baby when you have high blood pressure in pregnancy. Preeclampsia is a condition that occurs only during pregnancy and involves new onset of high blood pressure in pregnancy, usually after 20 weeks. If you do not have protein in the urine, this condition is usually referred to as gestational hypertension; if you have protein in the urine it is referred to as preeclampsia.
Women who are having their first baby, have had preeclampsia in a previous pregnancy, have chronic hypertension, are having twins or triplets, are pregnant from in-vitro fertilization, are older than 40, or have diabetes are all at a higher risk for developing high blood pressure in pregnancy. For this reason, it is important to attend your prenatal visits. Your doctor may order additional blood and urine tests to help you have a successful pregnancy.
The treatment for preeclampsia at full term is to deliver your baby, which will improve your health. However, that is not always the safest plan for the health of the baby. When these conditions develop too early in pregnancy, your OB provider will decide a treatment plan, which could include outpatient or inpatient observation, blood work or delivery. Medications to help lower your blood pressure may also be recommended.
For the initial treatment of high blood pressure in pregnancy, the three most commonly used medications are labetalol (Normodyne, Trandate), nifedipine (Procardia, Adalat) and methyldopa (Aldomet) and these are recommended above all other medications. Methyldopa has been used for decades to treat high blood pressure in pregnancy and it appears to be safe. Labetalol has been extensively studied and has become increasing prescribed in pregnancy. Labetalol is now commonly used as a first-line treatment choice. Nifedipine is also sometimes used in certain situations.
Certain blood pressure medications cannot be used in pregnancy. The use of angiotensin-converting enzyme inhibitors (ACE inhibitors), angiotensin receptor blockers (ARBs), renin inhibitors and mineralocorticoid receptor antagonists are not recommended while you are pregnant. Remember to always talk to your OB provider if you have questions about your blood pressure medication. Their goal is to help you have a safe pregnancy and a healthy baby.