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

E. Groeneveld, K. A. Broeze, M. J. Lambers, M. Haapsamo, K. Dirckx, B. C. Schoot, B. Salle, C. I. Duvan, R. Schats, B. W. Mol, P. G A Hompes

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28 Citations (Scopus)


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.

Original languageEnglish
Article numberdmr007
Pages (from-to)501-509
Number of pages9
JournalHuman Reproduction Update
Issue number4
Publication statusPublished - 1 Jul 2011


  • Aspirin
  • In vitro fertilization
  • Individual patient data meta-analysis

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynaecology

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