title: Factors influencing the time of introduction of steroidal contraception in the breast-feeding mother.
abstract: To ensure infertility whilst breast feeding many mothers ingest steroidal contraceptives. Animal experiments have shown how sexual differentiation of the brain occurs during perinatal life and can be affected by exogenous steroids. The amount of sex steroid secreted in the milk of lactating mothers is very small and dependent on the type of steroid chosen. "On demand" breast feeding is associated with a longer period of lactational amenorrhoea, obviating the necessity for early usage of contraceptives. In view of the possibility that sexual differentiation may be disturbed, it is suggested that, where steroidal contraception is required, the progesterone with the minimal amount of oestrogenic metabolite be used.
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development; D001942:Breast Feeding; D003276:Contraceptives, Oral / Q000009:adverse effects*; D003280:Contraceptives, Oral, Synthetic / Q000009:adverse effects* / Q000378:metabolism; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008895:Milk, Human / Q000378:metabolism; D011247:Pregnancy; D012733:Sex Differentiation / Q000187:drug effects; D013997:Time Factors
chemical_list: D003276:Contraceptives, Oral; D003280:Contraceptives, Oral, Synthetic