CALCIUM AND PHOSPHORUS IN MILK OF BRAZILIAN MOTHERS USING ORAL-CONTRACEPTIVES

Objective: Oral contraceptives (OC) are the most efficient method of c ontraception and it is the most prescribed by doctors in developing co untries. Therefore we studied the effects of combination pill and mini -pill on calcium and phosphorus in milk of breast-feeding mothers at d ifferent stages of lactation. Methods: Fifty-four breast-feeding mothe rs made up three study groups: 33 mothers who had been advised by thei r doctors to use either combination pill (12), or mini-pill (21), as w ell as a control group of 21 mothers that used no hormonal contracepti ves. All mothers completed a questionnaire and provided samples of mil k before and after a measured period of observation. Mean duration of study was 76, 120, and 101 days, respectively for users of mini-pill, combination pill, and controls. Determination of calcium and phosphoru s was done by inductively coupled plasma-atomic absorption spectrometr y. Results: Overall the decrease in milk concentrations of phosphorus (6%) and calcium (26.3%) during the study period was not influenced by OC treatment Regression analyses which took into consideration length of treatment, socioeconomic status, number of children, duration of p revious lactation. type of contraceptive, and age of mothers and repea ted measurements (before and after OC) showed that milk calcium was si gnificantly affected by stage of lactation (p=0.0013). Conclusion: The use of hormonal contraceptive such as the combination pill (levonorge strel 0.15 mg+ethynilestradiol 0.03 mg) and mini-pill (norethindone 0. 35 mg) does not seem to affect the secretion of calcium and phosphorus in milk of mothers.