Immediate postpartum initiation of etonogestrel-releasing implant: A randomized controlled trial on breastfeeding impact

Abstract

Background: Breast milk volume has never been evaluated when the etonogestrel (ENG) implant was inserted immediately postpartum. Thus, this study evaluated if the immediate postpartum insertion of the ENG implant alters breast milk volume.

Study design: Twenty-four postpartum women and their newborns (NBs) were randomized into two groups: Implant group (ENG implant inserted within 48 h after delivery) and Control group (absence of contraceptive method). The primary outcome was the amount of breast milk intake by the NBs in the first 6 weeks after delivery. Five and ten grams of deuterium (D(2)O) were orally administered to the postpartum women on the day of randomization (day 0) and on the 29th study day, respectively. Saliva samples were collected from the mother-NB pairs prior to each D(2)O dose administration and after D(2)O ingestion (periodic collection). The amount of breast milk ingested by the NBs was estimated by the amount of deuterium (D(2)O) ingested by the NBs through breastfeeding, using mass spectrometry in the saliva samples.

Results: Twenty-four postpartum women and their NB were randomized (12 per group). The median of breast milk intake by NBs following the two D(2)O doses were similar between groups {first D(2)O dose [Implant: 340 mL/day (240-420 mL/day) vs.

Control: 330 mL/day (300-530 mL/day), p=.54]; second D(2)O dose [Implant: 845 mL/day (770-980 mL/day) vs.

Control: 785 mL/day (680-980 mL/day), p=.63]}. The exclusive breastfeeding rate and NB weight were similar between groups in the first 6 weeks postpartum.

Conclusion: ENG implant insertion immediately postpartum does not alter the volume of breast milk intake by NBs.

Implications: Considering the benefits of immediate postpartum initiation of ENG implant on reducing unintended pregnancy and pregnancy recurrence, especially in vulnerable populations, our study adds safety data on breastfeeding effect of this practice.

Keywords: Breastfeeding; Contraception; Deuterium; Etonogestrel.