Progestin contraceptive used as a single product or linked to ethinyl estradiol (see Etinilestradiol + Norethindrone). Norethindrone is a progestin derivative of 19-nortestosterone. It is excreted in breast milk in clinically significant amount and no problems have been observed in infants whose mothers took it. Plasma levels of these infants were undetectable or very low. Progestin is generally considered contraceptive drugs of choice during lactation since it neither alter the quantity and composition of milk nor cause side effects on both growth of infants and the duration of breastfeeding.Published study results have shown protection against breast bone mass loss with the use of progestin-only contraceptives. For the first 6 weeks postpartum, non-hormonal methods are of choise. There is a debate on the role of progestin-related drugs in decreasing milk production when used before lactation has been fully established. The American Academy of Pediatrics states that this medication is usually compatible with breastfeeding.WHO List of Essential Medicines 2002: rates it as compatible with breastfeeding after the 6th postnatal week.