br Progestogens and autoimmune diseases br
Progestogens and autoimmune diseases
Introduction The benefits of breastfeeding for both women and their infants are considerable , , . The World Health Organization (WHO) recommends infants breastfeed exclusively during the first months of life . Although women breastfeeding exclusively and on demand are unlikely to conceive before 6weeks postpartum, many women discontinue fully breastfeeding before that time and are at risk of repeat pregnancy . Because birth spacing has demonstrated health benefits for women and infants, early initiation of contraception in the postpartum period may improve outcomes. Progestogen-only and progesterone contraceptives have been in use for years; however, their dosages and formulations have changed over time. Methods available include progestogen-only pills (POPs), progestogen and progesterone implants, injectables, progesterone rings and progestogen-releasing intrauterine devices (IUDs). They are highly effective when used as directed . The use of progestogen-only methods of contraception [progestogen-only contraceptives (POCs)] during the period of lactation has raised concerns for negative effects . Progestogens could interfere with lactogenesis, especially immediately postpartum , and have been shown to be transferred to breast milk . Animal data suggest that progesterone receptors are common in the developing rat ornidazole receptor . It is therefore possible that POCs may affect infant health or development . The large loading dose of progestogens found in the injectable depot medroxyprogesterone acetate (DMPA) has been particularly called into question . This systematic review was conducted for the WHO\'s Medical Eligibility Criteria for Contraceptive Use (MEC)  and examines the effects of POCs on outcomes such as breastfeeding performance and infant growth, development and health. It updates a previous review from 2010 .
Methods We followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for the conduct of systematic reviews. 
Results The literature search yielded 848 articles; 771 were excluded on title and abstract review and 28 were excluded after full-text review, leaving 49 reports meeting inclusion criteria. Since this review was last updated in 2008 , four new randomized controlled trials (RCTs) , , ,  and five new observational studies were published , , , , , and an additional five observational studies that were not included in the 2008 review were identified , , , , , for a total of eight reports of RCTs and 41 reports of nonrandomized clinical trials or observational studies for review (Table 1). These 49 articles reported on 47 different studies investigating the use of POCs in breastfeeding women and reported clinically relevant outcomes of infant growth, health or breastfeeding performance. Results for Key Question One, then for Key Question Two, are presented by study design and by time of contraceptive initiation: less than 6weeks or greater than or equal to 6weeks postpartum. Newly identified studies are presented first, followed by a brief summary of findings from the previous review. Nonrandomized clinical trials are presented together with observational data.
Discussion Overall, evidence from 49 articles reporting on 47 studies on use of POCs during breastfeeding is of poor to fair methodological quality. Of the 14 studies that were newly included in this review, four were older studies , , ,  of poor quality and one was published in 1999 and of fair quality . None of these older studies showed any negative effect of use of POCs on breastfeeding or infant outcomes. Of the nine studies that were published since the last review, four were RCTs. One of the four trials suggested that early, compared with delayed, postpartum initiation of the LNG-IUD was associated with shorter breastfeeding duration and less breastfeeding exclusivity at 6months . However, two other RCTs found no differences , . The fourth new trial provides indirect evidence demonstrating no difference in outcomes between POPs compared with COCs . Among the newly identified observational studies, findings were generally consistent with the observational studies in the previous review, with no adverse effects noted on breastfeeding or infant outcomes.