Birth control pill that contains the combination of an estrogen (Mestranol) and a progestin (Cholrmadinone) for oral use. Mestranol is a synthetic estrogen that is metabolized to Ethinylestradiol with similar actions as estradiol. A latest update no published data on excretion in breast milk, found were found. However, it is known that its metabolite Ethinylestradiol is excreted into milk in no or small amount.There is evidence (albeit inconsistent) that estrogen-containing pills may decrease milk production, especially during the first few weeks postpartum with a daily dose above 30 micrograms of ethinyl estradiol.It may reduce the protein content of the milk.No problems have been observed in infants whose mothers were treated, except one isolated case of transient gynecomastia. Chlormadinone is a synthetic progestin that is similar to progesterone. No changes in prolactin levels or milk production in women treated with chlormadinone were observed. With other similar combined contraceptives no differences have been observed in the frequency of breastfeeding or the amount of milk produced or weight gain of breastfed infants compared to other contraceptive methods (intrauterine devices, isolated progestogens). However, it would be advisable to avoid them until breastfeeding is well established (4-6 weeks). During lactation, progestin-only contraceptive pills are preferred to Estrogen containing ones, otherwise, the lowest estrogen dose should be usedWithin the first 6 postpartum weeks, non-hormonal methods are in the first line of choice. Hormone containing contraceptives do not affect the composition of milk, minerals (Mg, Fe, Cu, Ca, P) fat, lactose and calories but only a few the proteins.