Low-dose aspirin for in vitro fertilization or intracytoplasmic sperm injection: a systematic review and a meta-analysis of the literature

. Background: It was hypothesized that low-dose aspirin could improve implantation rates in subsequent pregnancies in women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). Previous studies have shown inconclusive results or focused on surrogate endpoints. We therefore conducted a systematic review and meta-analysis of the literature investigating the effect of low-dose aspirin on hard outcomes, including live birth rate, pregnancy rate and miscarriage. Methods: MEDLINE and EMBASE databases were searched up to November 2011. Randomized controlled trials comparing low-dose aspirin with placebo/no treatment in IVF/ICSI women were included. Pooled odds ratios (ORs) and 95%confidence intervals (CIs) were calculated. Results: Seventeen studies with 6403 patients were included. The use of aspirin did not improve live birth pregnancy rate compared with placebo or no treatment (1.08; 95% CI, 0.90, 1.29). Pregnancy rates were significantly increased in patients randomized to low-dose aspirin (OR, 1.19; 95% CI, 1.01, 1.39), but miscarriage rates were not (OR, 1.18; 95% CI, 0.82, 1.68). Results of sensitivity analyses including high-quality studies did not show statistically significant differences in all considered endpoints. Conclusions: The results of this study do not show a substantial efficacy of aspirin inwomen undergoing IVF/ICSI and do not support the use of low-dose aspirin to improve the success of IVF/ICSI in terms of pregnancy outcomes. Further high-quality studies evaluating the possible efficacy of aspirin in selected groups of patients are warranted.