Abstract

PIP: Because of confusing experimental evidence on the effect of oral contraceptives on lactation, a new experiment administering a combination of norethindrone 1 mg with mestranol 0.08 mg or a placebo labelled as this contraceptive to 50 nursing mothers (Group I) was conducted in 1967 to try and obtain conclusive results. 50 other nursing patients (Group II) were used as controls. Quantity and quality of breast milk was determined by daily measurements of baby weight gain, supplemental feedings, and length of lactation. Baby weight gain in Group I mothers using the contraceptives was significantly lower than the control group, despite increase in supplemental calories given to the infants. The duration of lactation was also decreased significantly. This effect was more pronounced in primiparas when compared with those with previous lactation success. Involution of infant breast tissue and maternal genitals were examined and revealed no apparent effects from the contraceptive treatment. Oral contraceptives appear to be contraindicated in lactating mothers.