Hypertension is the most common medical problem encountered in pregnancy and remains an important cause of maternal, and fetal, morbidity and mortality. It complicates up to 15% of pregnancies and accounts for approximately a quarter of all antenatal admissions.
Hypertension in pregnancy is diagnosed either from an absolute rise in blood pressure or from a relative rise above measurements obtained at booking. The convention for the absolute value is a systolic > 140 mm Hg or a diastolic > 90 mm Hg.
Sometimes high blood pressure is present before pregnancy. In other cases, high blood pressure develops during pregnancy. For example:
• Chronic hypertension. If high blood pressure develops before pregnancy, during pregnancy but before 20 weeks or lasts more than 12 weeks after delivery, it's known as chronic hypertension.
• Gestational hypertension. If high blood pressure develops after 20 weeks of pregnancy, it's known as gestational hypertension. Gestational hypertension usually goes away after delivery.
• Preeclampsia. Sometimes chronic hypertension or gestational hypertension leads to preeclampsia, a serious condition characterized by high blood pressure and protein in the urine after 20 weeks of pregnancy. Left untreated, preeclampsia can lead to serious — even fatal — complications for mother and baby.
National Heart, Lung and Blood Institute, US suggests that if you are thinking about having a baby and you have high blood pressure, talk first to your doctor or nurse. Taking steps to control your blood pressure before and during pregnancy - and getting regular prenatal care - go a long way toward ensuring your well-being and your baby's health.
• Be sure your blood pressure is under control. Lifestyle changes such as limiting your salt intake, participating in regular physical activity, and losing weight if you are overweight can be helpful.
• Discuss with your doctor how hypertension might affect you and your baby during pregnancy, and what you can do to prevent or lessen problems.
• If you take medicines for your blood pressure, ask your doctor whether you should change the amount you take or stop taking them during pregnancy. Experts currently recommend avoiding angiotensin-converting enzyme (ACE) inhibitors and Angiotensin II (AII) receptor antagonists during pregnancy; other blood pressure medications may be OK for you to use. Do not, however, stop or change your medicines unless your doctor tells you to do so.
• Obtain regular prenatal medical care.
• Avoid alcohol and tobacco.
• Talk to your doctor about any over-the-counter medications you are taking or are thinking about taking.
According to Mayo Clinic, high blood pressure during pregnancy poses various risks, including:
• Decreased blood flow to the placenta. This reduces the baby's supply of oxygen and nutrients, potentially slowing the baby's growth and increasing the risk of a low birth weight.
• Placental abruption. With this condition, the placenta prematurely separates from the uterus. Placental abruption can deprive the baby of oxygen and cause heavy bleeding in the mother.
• Premature delivery. Sometimes an early delivery is needed to prevent potentially life-threatening complications.
• Future cardiovascular disease. Women who develop preeclampsia — a serious condition characterized by high blood pressure and protein in the urine after 20 weeks of pregnancy — might be at increased risk of cardiovascular disease later in life, despite the fact that their blood pressure returns to normal after delivery.
Any medication you take during pregnancy can affect your baby. Although some medications used to lower blood pressure are considered safe during pregnancy, others — such as angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and renin inhibitors — are generally avoided during pregnancy.
Treatment is important, however. The risk of heart attack, stroke and other problems associated with high blood pressure doesn't go away during pregnancy. And high blood pressure can be dangerous for your baby, too. If you need medication to control your blood pressure during pregnancy, your health care provider will prescribe the safest medication at the most appropriate dose. Take the medication exactly as prescribed. Don't stop taking the medication or adjust the dose on your own.
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