Influence of Norplant contraceptive implants on lactation and infant growth]

A pilot study to evaluate effects of the contraceptive implant system was conducted in Chile. 200 mothers aged 18-35 years having their first second or third child in a maternity hospital in Santiago were selected for the study. 100 of the women had the inserted on about the 55th postpartum day and the other mothers had copper T-380 IUDs inserted. All the women breastfed exclusively and their babies showed adequate growth. All mothers and infants were in good health. Control visits occurred 10 20 and 30 days after insertion and subsequently at monthly intervals until the end of the first year. There were no significant differences in the 2 groups of mothers in age weight hemoglobin level or parity. There were 47 sons and 53 daughters in the Norplant group vs 52 sons and 48 daughters in the IUD group. 14 Norplant cases and 20 controls were excluded from the study during the year due to illness of the mother or baby IUD removal employment of the mother causing long separations from the baby loss to follow-up or change of residence. There were no significant differences in the proportions of women exclusively breast feeding until the 12th month when fewer mothers did so. No significant differences were found in the timing of weaning. At 6 and 12 months postpartum 8% and 37% of the Norplant group and 8% and 37% of the IUD group were weaned. Both groups of infants showed normal weight gains but girls in the Norplant group had a significantly lower weight gain in the 4th month than girls in the IUD group. No pregnancies were diagnosed in either group. No women requested implant removal but 2 IUDs were removed 1 in the 7th month and 1 in the 11th month. No significant side effects of treatment were observed. 1 infant in the Norplant group died at 8 months from hepatitis followed by bronchial pneumonia. Bleeding irregularities were rare in Norplant users. Variable concentrations of levonorgestrel were found in samples of milk taken during the first 40 days of Norplant use when concentrations are highest. Individual values ranged from 23-311 pg/ml. The dose received by the infant was estimated at 15-18 ng/kg/day during the 1st month of treatment. The data suggest that Norplant had no negative influence on lactation. Although problems of levonorgestrel transference through maternal milk appear to be minimal longterm studies are required to confirm their innocuity. Until then norplant use in lactating women should be limited to cases requiring effective contraception in which nonhormonal methods are contraindicated or unacceptable.