Aspirin in women undergoing in vitro fertilization treatment: a systematic review and meta-analysis.

OBJECTIVE Many trials have evaluated the effects of aspirin in women undergoing IVF or intracytoplasmic sperm injection (ICSI) treatment. These trials have generally shown inconclusive or inconsistent findings. We conducted a systematic review of trials of aspirin during IVF or ICSI treatment to generate more precise estimates of effects and attempt to explore the reasons for the inconsistencies. DESIGN A systematic review and meta-analysis. SETTING Assisted conception units in different countries. PATIENT(S) Seven trials including 1,241 women undergoing controlled ovarian hyperstimulation (COH), IVF, or ICSI and day 3 embryo transfer. INTERVENTION(S) Low-dose aspirin supplementation versus placebo or no supplementation. MAIN OUTCOME MEASURE(S) Clinical pregnancy and live birth. RESULT(S) Searches were conducted in MEDLINE, EMBASE, Cochrane Library, ISI Proceedings, and SCISEARCH, and all randomized controlled trials that evaluated the effectiveness of aspirin compared to placebo or no treatment in women undergoing IVF-ICSI treatment were included. Study selection, quality appraisal, and data extractions were performed independently and in duplicate. Seven relevant trials were identified. Meta-analysis of these studies did not show a significant benefit of aspirin therapy in improving clinical pregnancy rate (relative risk [RR] 1.11, 95% confidence interval [CI] 0.95, 1.31) or live birth rate (RR 0.94, 95% CI 0.64, 1.39). There was no significant difference in miscarriage rate (RR 1.06, 95% CI 0.53, 2.11) or ectopic pregnancy rate (RR 2.24, 95% CI 0.70, 7.24). An improvement was noted in uterine artery pulsatility index (weighted mean difference: -0.78, 95% CI -0.87, -0.69) in women taking low-dose aspirin. The evidence regarding other outcomes was either not significant or contradictory. CONCLUSION(S) Currently available evidence does not support the use of aspirin in IVF or ICSI treatment. However, the noted trend of improvement in clinical pregnancy, and the lack of power even when the studies were pooled highlight the need for a definitive trial.