Progestogen-only contraceptive use among breastfeeding women: a systematic review.

BACKGROUND Postpartum women need effective contraception. Concerns have been raised that use of progestogen-only contraceptives (POCs) may affect breastfeeding performance and infant health outcomes. OBJECTIVES We investigated the clinical outcomes of breastfeeding duration, initiation of supplemental feeding and weaning, as well as infant outcomes including infant growth, health and development among breastfeeding women using POCs compared with breastfeeding women not using POCs. SEARCH STRATEGY We searched the PubMed database for all articles published from database inception through December 2014. SELECTION CRITERIA We included primary research studies of breastfeeding women of any age or parity who received POCs, including progestogen-only pills, injectables, implants or hormonal intrauterine devices (IUDs). The main outcomes were breastfeeding performance (as measured by initiation, continuation, frequency and exclusivity of breastfeeding) and infant health (as measured by growth, development or adverse health effects). RESULTS Forty-nine articles reporting on 47 different studies were identified that investigated the use of POCs in breastfeeding women and reported clinically relevant outcomes of infant growth, health or breastfeeding performance. Studies ranged from poor to fair methodological quality and generally failed to show negative effects of the use of POCs on breastfeeding outcomes or on infant growth or development. One randomized controlled trial (RCT) raises concerns that immediate insertion of the levonorgestrel IUD postpartum may be associated with poorer breastfeeding performance when compared with delayed insertion, although two other RCTs evaluating early etonogestrel implants compared with delayed initiation of implants or depot medroxyprogesterone acetate failed to find such an association. CONCLUSION The preponderance of evidence fails to demonstrate adverse breastfeeding outcomes or negative health outcomes in infants such as restricted growth, health problems or impaired development. Evidence newly added to this review was largely consistent with previous evidence.