Barbados Low Dose Aspirin Study in Pregnancy (BLASP): a randomised trial for the prevention of pre-eclampsia and its complications

Abstract

Objective: To determine whether prophylactic, low dose controlled-release aspirin improves outcome for pregnant women and their babies in Barbados.

Design: Randomised placebo-controlled trial.

Setting: The Queen Elizabeth Hospital, Barbados.

Population: All women attending antenatal clinics between 12 and 32 weeks of gestation were eligible, if without specific contraindications to aspirin and unlikely to deliver immediately.

Methods: Randomisation was computer-generated in the antenatal clinic; 1822 women were allocated to receive 75 mg controlled-release aspirin and 1825 matching placebo.

Main outcome measures: Proteinuric pre-eclampsia, other pregnancy-induced hypertension, pregnancy duration, birthweight, stillbirths and neonatal deaths, major neonatal events.

Results: All but three women from each group were followed up successfully. Forty-four percent were primigravid, and 8% had previous obstetric complications. There were no significant differences between the allocated treatment groups in the incidence of proteinuric pre-eclampsia (40 [2.2%] of those allocated aspirin, compared with 46 [2.5%] allocated placebo), of preterm delivery (255 [14.0%] vs 270 [14.8%]), of birthweight < 1500 g (32 [1.7%] vs 33 [1.8%]) or of stillbirth and neonatal death (44 [2.4%] vs 38 [2.1%]). Aspirin was not associated with excess risk of maternal or fetal bleeding.

Conclusions: The results of this study in Barbados do not support the routine use of low dose aspirin for prevention of pre-eclampsia or its complications, confirming results of previous large trials in other settings.

PIP: The effect of administration of a prophylactic dose of controlled-release aspirin on the prevention of pre-eclampsia was investigated in a randomized placebo-controlled trial conducted at the Queen Elizabeth Hospital in Barbados in 1992-94. All women attending hospital antenatal clinics between 12 and 32 weeks of gestation were eligible for the study; enrolled were 1822 cases allocated to receive 75 mg of aspirin per day and 1825 matched controls who received a placebo. Study participants represented about 60% of women who gave birth during the enrollment period. Aspirin administration was not associated with any excessive risk of infant or maternal bleeding. However, there were no significant differences between cases and controls in terms of the incidence of proteinuric pre-eclampsia (2.2% vs. 2.5%), preterm delivery (14.0% vs. 14.8%), birth weight under 1500 g (1.7% vs. 1.8%), or stillbirth and neonatal death (2.4% vs. 2.1%). These results were not affected by the time of pregnancy at which aspirin prophylaxis was initiated or parity. The Barbados findings are consistent with previous studies and fail to support the routine use of low-dose aspirin for the prevention of pre-eclampsia and its complications.