MONDAY, Aug. 3, 2009 (HealthDay News) -- Labor should be induced after 37 weeks in pregnant women with mild hypertension disorders such as high blood pressure and mild preeclampsia, according to a new study in The Lancet.
The study included 756 pregnant women in the Netherlands. All had been pregnant 36 to 41 weeks and had gestational hypertension or mild preeclampsia. Some of the women underwent induced labor and others were monitored as their pregnancies continued.
The two groups were compared on a number of measures that the researchers labeled as poor maternal outcome, including death, eclampsia, pulmonary edema, progression to severe high blood pressure, major post-birth bleeding (loss of a liter or more of blood), and what's known as HELLP syndrome (hemolysis, elevated liver enzymes and low platelet, or red blood cell, count).
Poor maternal outcome occurred in 31 percent of the women who had induced labor and in 44 percent who were monitored. For women who had induced labor, that equated to a 29 percent lower risk for developing poor maternal outcome than those who were monitored, the study reported.
The findings appear online Aug. 3 in The Lancet.
The researchers also found that women who had induced labor had fewer cesarean sections than those in the monitored group.
"The results of our trial are important for both developed countries in which induction of labor in women with hypertensive disease beyond 36 weeks' gestation has been controversial, and for developing countries in which maternal morbidity and mortality rates are substantially increased," wrote Dr. Corine M. Koopmans, of the University Medical Centre Groningen, and colleagues.
"Our finding that induction of labor was associated with a reduced risk of severe hypertension or HELLP syndrome and subsequent need for cesarean section emphasizes the importance of frequent blood pressure monitoring during the concluding weeks of pregnancy," they added.
The study authors concluded that "induction of labor should be advised for women with gestational hypertension and a diastolic blood pressure of 95 mm Hg or higher or mild preeclampsia at a gestational age beyond 37 weeks."
The U.S. National Heart, Lung, and Blood Institute has more about high blood pressure during pregnancy.