Is aspirin effective in women undergoing in vitro fertilization (IVF)? Results from an individual patient data meta-analysis (IPD MA).

BACKGROUND: Aspirin is believed to improve the outcome of IVF, but previous conventional meta-analyses on the subject are conflicting. Therefore, we performed a meta-analysis with individual patient data (IPD MA) of randomized clinical trials (RCTs) on the subject. METHODS: A systematic literature search was conducted to identify RCTs assessing the effectiveness of aspirin in IVF. Authors were asked to share their original data. In a one step meta-analytic approach, the treatment effect of aspirin was estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression, based on the intention to treat principle. RESULTS: Ten studies fulfilled the inclusion criteria. Authors of six studies provided IPD, including 1119 patients (562 placebo and 557 aspirin). There were 160 clinical pregnancies in the aspirin (28.8%) and 179 (31.9%) in the placebo group [OR 0.86, 95% CI (0.69-1.1)]. There were 129 ongoing pregnancies in the aspirin (23.6%) and 147 in the placebo group (26.7%) [OR 0.85, 95% CI (0.65-1.1)]. Whereas the conventional meta-analysis limited to studies that could provide IPD showed an OR of 0.89 (95% CI 0.69-1.2), the conventional meta-analysis limited to the eight studies of which method of randomization could be confirmed showed an OR of 0.94 (95% CI 0.76-1.17) and the conventional meta-analysis including all 10 eligible RCTs identified with our search changed the OR to 1.07 (95% CI 0.81-1.41). This difference in direction of effect, derived from the studies not able to share IPD of which quality of randomization could not be confirmed. CONCLUSIONS: Aspirin does not improve pregnancy rates after IVF.

Does low-dose aspirin improve pregnancy rate in IVF/ICSI? A randomized double-blind placebo controlled trial.

BACKGROUND: It has been suggested in the literature that low-dose aspirin leads to an increased number of oocytes in IVF/ICSI as well as a higher pregnancy rate. The aim of the present study was to investigate the effect of daily administration of low-dose aspirin, compared with placebo, on pregnancy rate in IVF and ICSI. METHODS: This study was a prospective, randomized, double-blind placebo controlled trial, performed in the fertility centre of the University Hospital of Ghent. Concealed allocation by computerized randomization was done by the central pharmacy of the hospital. Daily oral administration of aspirin 100 mg or placebo started before stimulation and was continued until confirmation of pregnancy by detection of fetal heart activity on ultrasound. The primary outcome measure assessed in this trial was clinical pregnancy rate per cycle. RESULTS: Two hundred and one couples were included in this study, 193 women (aspirin group n = 97, placebo group n = 96) started treatment and 181 underwent an embryo transfer. There were 31 clinical pregnancies (31/97 or 32%) in the aspirin group versus 30 (30/96 or 31%; P = 0.916; OR 1.033; 95% CI 0.565-1.890) in the placebo group. CONCLUSIONS: This randomized controlled trial could not show a significant difference in clinical pregnancy rate between the aspirin and the placebo group in a first or second IVF/ICSI cycle. Given the lack of evidence for a beneficial effect of low-dose aspirin, it appears that low-dose aspirin should not be prescribed routinely in IVF/ICSI treatment. ClinicalTrials.gov Identifier: NCT00644085.