Nighttime is the right time to prevent preterm labor with aspirin.

2002 NOV 21 - (NewsRx.com & NewsRx.net) -- Low-dose aspirin prevented preterm labor in pregnant women at risk for high blood pressure, but only if they started therapy before the 16th week of pregnancy, and only if they took it at night, according to research presented at the American Heart Association's 56th Annual High Blood Pressure Research Conference.

"This is the first study to show that aspirin at bedtime works and aspirin at awakening does not," said lead author Ramon C. Hermida, PhD, director of the bioengineering and chronobiology laboratories and a professor at the University of Vigo in Vigo, Spain. He added that earlier studies may have had conflicting results because they used lower aspirin doses, started therapy later in pregnancy or gave it at different times of the day.

The double-blind, randomized controlled trial followed 341 pregnant women who were at high risk for blood pressure problems due to obesity, family or personal history of gestational high blood pressure or pre-eclampsia, or a history of miscarriage.

The women were divided into 6 groups and given 100 mg of aspirin or placebo at 1of 3 times: on awakening, 8 hours later or at bedtime. Treatment started at 12 to 16 weeks of pregnancy.

Compared with placebo, there was no effect on blood pressure when aspirin was taken in the morning. However, blood pressure was significantly reduced when the women took aspirin 8 hours after ...