The efficacy of antihypertensive treatment in pregnant women with chronic and gestational hypertension: a population-based study.

The efficacy of antihypertensive treatment was investigated in pregnant women with chronic hypertension (CH) or gestational hypertension (GH) on the basis of the occurrence of pregnancy complications and adverse birth outcomes. Medically recorded pregnancy complications and birth outcomes of 1579 pregnant women with CH and 1098 pregnant women with GH were compared to 34,633 pregnant women without CH, GH, preeclampsia-eclampsia or any secondary hypertension who delivered newborn infants without defects in the population-based data set of the Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980-1996. Of 1579 (4.1%) pregnant women with CH, 1522 (96.4%) were treated with antihypertensive drugs. Of 1098 (2.9%) pregnant women with GH, 657 (59.8%) were treated. Pregnant women with treated CH had a higher risk of threatened abortion, preterm delivery, and placental disorders, in addition to low-birthweight newborns. However, pregnant women with untreated CH and GH had no higher risk of pregnancy complications or adverse pregnancy outcomes. Antihypertensive treatments were not able to neutralize the harm of severe CH in pregnant women, the antihypertensive treatments were not appropriate and/or effective, or related drug treatments may contribute to these adverse effects.