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

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.

The Barbados low-dose aspirin in pregnancy (BLASP): a population based trial in a developing country with excess pre eclampsia and perinatal mortality

A large randomised controlled double blind trial (RCT), BLASP was set up in Barbados' one main maternity centre (QEH). Almost all women at 12-32 weeks attending for antenatal booking were eligible in the period July 1992-1994. After consent, entry details were recorded on a computer with random allocation to either a slow-release 75 mg aspirin (A) or a placebo (P). Intention-to-treat analysis, based on the 3,643 randomized pregnant women (1,819 allocated aspirin and 1,824 a placebo), is viewed in context of all other randomised control trials (RCTs). Entry date balanced in A and P for gestational age of 20.2 weeks, average maternal age 24 years, more than half aged 20-29 years and 44 percent primigravidae. Previous obstetric complications were lower than expected at 5 percent. Family histories of diabetes mellitus and hypertension were high (> 33 percent). Compliance was moderate with 36 percent taking allocated tablets for more than 95 percent of the time, but a third for less than 80 percent. There were no serious side effects, and in particular no bleeding. PE rates were low at 2.2 percent in A and 2.5 percent in P, a 13.3 percent odds reduction with wide 95 percent CI showing no significant effect. A tendency in all predefined categories (PE + PIH, etc.) for fewer cases in A (n=203, 11.2 percent) than in P (n=231, 12.7 percent) is not confirmed in an overview of all trials. Antenatal hospital admissions occurred in 34 percent of A and 33 percent of P. There was no difference in very low-birth-weight (<1500 g) but rates were 7 percent in A and 8.3 percent in P for birthweight between 1,500 and 2,499 g. Mean pregnancy duration was virtually identical at 38.7 (SD 3.6) weeks. Stillbirths and neonatal death rates were 2.3 percent and 2 percent, and Caesarean Sections 13.6 and 13.8 percent, in A and P, respectively. It is concluded that in this large RCT conducted in the Caribbean (BLASP), there were no meaningful differences between those allocated aspirin or placebo but event rates were low, perhaps due to the "healthier recruit" effect. In the context of all other published randomised trials, these results confirm that aspirin has little effect on the prevention of PE or PIH or other specified outcomes but is entirely safe (AU)