ABSTRACT
Hypertension accounts for up to 25% of antenatal admissions and much of antenatal care, especially in the second half of pregnancy, is aimed at the detection of hypertension and pre-eclampsia. Cardiac output increases during pregnancy and peripheral resistance falls, so that the maternal blood pressure falls in the first trimester, reaches a nadir in the second trimester and returns to pre-pregnancy levels in the third trimester. Chronic hypertension may be present before, or begin during, pregnancy. Most complications are related to superimposed pre-eclampsia, which leads to a significantly higher incidence of intrauterine growth retardation (IUGR), premature delivery, Caesarean section, placental abruption and increased perinatal mortality. Treatment of mild to moderate hypertension is of no benefit to the fetus, and does not prevent progression to severe hypertension or pre-eclampsia. Methyldopa is the antihypertensive of choice in pregnancy even though it is no longer first line in non-pregnant patients.
