Effects of the etonogestrel-releasing contraceptive implant (Implanon((R))) on parameters of breastfeeding compared to those of an intrauterine device

Eighty healthy single births born at a gestational age of 259-294 days were studied in an open, non-randomized, group comparative fashion. The mothers were on average 6 weeks postpartum, healthy, and fully breastfeeding at th e start of treatment. Forty-two mothers elected to use the etonogestrel-rel easing implant, Implanon(R), while 38 chose use of a non-hormone medicated intrauterine device (IUD). One month after implant placement, the dose of e tonogestrel ingested by the infants via breast milk was 19.86 ng/kg/day, wh ich decreased to 10.45 ng/kg/day at the end of the study period (month 4). The: volume of breast milk production was not affected by the use of Implan on. There were no significant differences between groups in milk content of total fat, total protein, and lactose. The timing and quantity of suppleme ntary feedings did not differ between the two groups. Growth of the infants was analyzed by treatment and gender. For the girls, no differences betwee n groups were seen for body weight, body length, and head circumference. Th e same applied to the boys except for a somewhat larger, although not stati stically significant, increase in body weight for boys whose mother used Im planon. There was a low incidence of intercurrent illnesses in the infants of both groups. None of the conditions was of a serious nature. From the pr esent study, we conclude that Implanon did not change the volume and compos ition of breast milli. The low concentration of etonogestrel ingested by th e infant was not associated with adverse effects. (C) 2001 Elsevier Science Inc. All rights reserved.