Objectives: To estimate, from the literature, when nonlactating postpartum women regain fertility.
Data sources: We searched PubMed and Cochrane Library databases for all articles (in all languages) published in peer-reviewed journals from database inception through May 2010 for evidence related to the return of ovulation and menses in nonlactating postpartum women. Search terms included "Fertility" (Mesh) OR "Ovulation" (Mesh) OR "Ovulation Detection" (Mesh) OR "Ovulation Prediction" (Mesh) OR fertility OR ovulat* AND "Postpartum Period" (Mesh) OR postpartum OR puerperium AND Human AND Female.
Methods of study selection: We included articles assessing nonlactating women's first ovulation postpartum. Studies in which women breastfed for any period of time or in whom lactation was suppressed with medications were excluded.
Tabulation, integration and results: We identified 1,623 articles; six articles reported four studies met our inclusion criteria. In three studies utilizing urinary pregnanediol levels to measure ovulation, mean day of first ovulation ranged from 45 to 94 days postpartum; 20%-71% of first menses were preceded by ovulation and 0%-60% of these ovulations were potentially fertile. In one study that used basal body temperature to measure ovulation, mean first ovulation occurred on day 74 postpartum; 33% of first menses were preceded by ovulation and 70% of these were potentially fertile.
Conclusion: Most nonlactating women will not ovulate until 6 weeks postpartum. A small number of women will ovulate earlier, potentially putting them at risk for pregnancy sooner, although the fertility of these early ovulations is not well-established. The potential risk of pregnancy soon after delivery underscores the importance of initiating postpartum contraception in a timely fashion.