A systematic review of early postpartum medroxyprogesterone receipt and early breastfeeding cessation: evaluating the methodological rigor of the evidence.

BACKGROUND Breastfeeding has numerous maternal and infant benefits. Progesterone contraception after birth is frequently recommended, but because a decrease in progesterone is required to initiate lactation, early postpartum progesterone contraception use could inhibit lactation. The purpose of this article is to critically evaluate the scientific basis for conflicting clinical recommendations related to postpartum medroxyprogesterone use among breastfeeding women. METHODS Relevant peer-reviewed literature was identified through a comprehensive search of PubMed through December 2010. The search was restricted to clinical trials, randomized clinical trials, or comparative studies written in English and conducted among humans. The studies included in this review addressed the effect of medroxyprogesterone administration at <6 weeks postpartum on breastfeeding exclusivity and/or duration and measured breastfeeding outcomes at ≥ 6 weeks postpartum. RESULTS Of the 20 articles identified, only three studies satisfied the inclusion criteria. However, all three studies were of low-quality methodological rigor, and none accounted for potential confounders. CONCLUSION Current evidence is methodologically weak and provides an inadequate basis for inference about a possible causal relationship between early postpartum medroxyprogesterone use and poor breastfeeding outcomes. However, given the presence of a strong biological model describing the potential deleterious effect of postpartum medroxyprogesterone use on lactation, further research that improves on current literature is warranted. Meanwhile, we recommend that potential breastfeeding risks associated with early (<6 weeks) postpartum medroxyprogesterone use be disclosed to allow for a fully informed consent and decision-making process.