The role of aspirin dose and initiation time in the prevention of preeclampsia and corresponding complications: a meta-analysis of RCTs.

purposeTo investigate the role of different dosages and initial times of aspirin in preeclampsia prevention.

methodsThis meta-analysis was performed based on randomized-control trials (RCTs). RCTs of women assigned to receive low-dose aspirin, placebo, or no treatment were included. Preeclampsia and corresponding complications were pooled for analysis. All studies were retrieved from PubMed, Embase, Cochrane and Web of Science.

resultsA total of 46 studies were obtained in this meta-analysis, which consisted of 24,028 participants. When women at ≤ 16 gestational weeks started treatment with a dosage of < 100 mg/day aspirin, there was a significant reduction in the incidence of preeclampsia (RR = 0.75; 95% CI 0.58-0.98; P = 0.03), while in the subgroup receiving ≥ 100 mg/day aspirin, the result was RR = 0.71 (95% CI 0.53-0.95; P = 0.02). When aspirin was initiated at > 16 weeks, with a dosage of < 100 mg/day aspirin, there was a lesser preventive effect (RR = 0.80; 95% Cl 0.64-1.00; P = 0.05), and there was no significance in the subgroup receiving ≥ 100 mg/day aspirin (RR = 0.76; 95% Cl 0.45-1.31;  P =  0.32). Furthermore, aspirin was revealed to have a protective effect on reducing preterm delivery, but there was an increased risk of postpartum hemorrhage. No significant result was obtained for fetal loss.

conclusionThe results of this meta-analysis suggest that high-risk pregnant women can prevent preeclampsia or preterm delivery by taking low-dose aspirin; the most efficient period is ≤ 16 weeks of gestation, and the best dose is ≥ 100 mg.