Women with mild or severe high blood pressure during pregnancy - a condition known as pre-eclampsia - should have labor induced after 37 weeks’ gestation, according to a new study.

Pre-eclampsia is a potentially dangerous condition that develops in the second or third trimester of pregnancy and involves the development of high blood pressure and the presence of protein in the urine.

Dr. Corine M. Koopmans, from University Medical Centre Groningen, the Netherlands, and colleagues assigned 756 women to induction of labor, using intravenous hormones or by breaking the water sac, or expectant management, in which obstetricians closely monitor the pregnancy. These women were drawn from an eligible group of 1153 women, of whom 397 refused to take part in the trial, permitted use of their medical records.

In women beyond 37 weeks’ gestation, inducing labor cut the risks of severe high blood pressure and the need for cesarean section. No infants or mothers died in either group, Koopmans’ team reports in The Lancet.

Based on the study, writes Dr. Donna D. Johnson, from the Medical University of South Carolina, Charleston, in a related editorial, inducing labor in women with high blood pressure during pregnancy “should be incorporated into clinical practice.”

SOURCE: Lancet 2009, advance online publication August 4, 2009.