In a long-term follow-up study 48 breast-fed children, whose mothers had used oral contraceptives containing 50 micrograms of ethinylestradiol while lactating, were compared to a matched control group whose mothers had not used any hormonal contraceptives during lactation. In spite of a very large number of data collected from several different sources of information, no effect could be demonstrated of the ingested steroid, neither upon the panorama of diseases nor upon intellectual or psychological behaviour of the infants and children up to 8 years of age. The mothers who used oral contraceptives lactated a significantly shorter period of time than the controls, but no differences were found in weight gain and height increase in the children between cases and controls.
PIP: When lactating women use hormonal contraceptives, small amounts of the steroids are transferred to the breast milk; these steroids can also be detected in infants' plasma after breastfeeding. In a long-term follow-up study 48 breast-fed children, whose mothers had used oral contraceptives (OCs) containing .50 microgram of ethinylestradiol while lactating, were compared to a matched control group whose mothers had not used hormonal contraceptives during lactation. The only significant difference between cases and controls was a shorter lactating period for the women who had used OCs. However, the study demonstrated no effect of the steroid ingested during the suckling period, neither upon the panorama of diseases nor upon intellectual or psychological behavior of the infants and children up to 8 years of age. The study looked at the 1st, 2nd, and 3rd consecutive illnesses of the children who became diseased as well as the age at debut and degree of difficulty; no significant differences were found between cases and controls. Nor were there any differences between the 2 groups according to a special control of 4-year old children or at school start. Also, no differences were found in weight gain and height increase between cases and controls. Admittedly, the present study includes a limited number of cases and controls. However, for each child a very large number of data was collected from several different sources of information and sets of data are complete for all cases and controls. The time period of observation in this prospective study is now 8 years; the study will be continued beyond puberty.