The possible effect of breastfeeding on intrauterine device (IUD) insertion events was investigated. Analysis included a total of 6493 women who enrolled in multicenter IUD clinical trials over a ten-year period. Findings indicate that breastfeeding exerts a protective effect on the incidence of moderate to severe insertional pain and reduces the need for cervical dilatation to facilitate insertion. The pain protection effect was most evident in breastfeeding women who were still in lactational amenorrhea. Subjects with amenorrhea, both breastfeeding and non-breastfeeding, had a significantly lower incidence of pain at IUD insertion than the corresponding menstruating subjects. This effect may be related to a higher secretion of beta-endorphin in the breastfeeding and lactational amenorrheic subjects.

The progestin-only oral contraceptive (POC) is not a widely-used method of contraception, possibly due to competition from other contemporary contraceptive methods or misunderstanding and prejudices among clients and/or service providers. Because of its underuse, the POC, as a contraceptive method, is under-studied. This article evaluates the general merits of the POC and its disadvantages relative to combined oral contraceptives (COCs) and other contraceptive methods, specifically during the postpartum period and particularly for breastfeeding women. We find that the POC appears to be a safe and acceptable contraceptive method for postpartum women who are fully or nearly fully breastfeeding at six months postpartum or when menstruation returns. The POC could be considered for use at any time by non-breastfeeding postpartum women. The need for empirical studies of the POC is also discussed.