Obesity is a critical public health issue in the United States.  Overweight and obese women are at risk of excessive gestational weight gain and postpartum weight retention.  Research shows that poor postpartum weight loss correlates with long-term obesity and associated comorbidities.  Contraceptive use in the postpartum period prevents unintended pregnancy and short inter-pregnancy intervals.  Women who conceive too quickly after delivery experience higher rates of preterm birth and other pregnancy complications.  Additionally, short inter-pregnancy intervals (less than 12 months) with or without excessive pregnancy weight gain, confers nearly a 2.5-fold increased risk of maternal obesity compared to normal inter-pregnancy intervals.  Long-acting reversible contraceptives provide several benefits for postpartum women, but the optimal contraceptive method for postpartum overweight and obese women is unknown.  The etonogestrel (ENG) subdermal implant is a safe and effective long-acting reversible method, but its effect on postpartum weight loss has not been determined.
The primary purpose of the study was to compare weight loss during the first 6 months postpartum in overweight and obese women using the etonogestrel-implant, placed in the immediate postpartum period, with that of controls using non-hormonal contraception.  The primary outcome was percent return to pregravid weight by 6 months postpartum of women in each group.  Secondary outcomes included waist circumference at 6 months postpartum and description of participants’ motivation to lose weight, eating habits, and physical activity in the first 6 months postpartum.
This study was a first step, prospective cohort study that analyzed women in three different groups based on degree of overweight and obesity as determined by body mass index (BMI) (overweight: 25-29.9 kg/m2; obese: 30-34.5 kg/m2; morbidly obese: 35-39.9 kg/m2) and grouped by use of the etonogestrel implant or non-hormonal contraception was performed for both primary and secondary outcomes.
From June 2014 through August 2015, a total of 127 women were recruited for participation.  Fifty-seven women chose the etonogestrel implant as their immediate postpartum contraceptive method and 70 chose a non-hormonal method.  Six months after delivery, about half of women in each group returned to within 1.5 kg of pre-pregnancy weight (45% ENG-implant versus 52% non-hormonal methods (52%; p=0.7).   Similar results were obtained when women were compared by BMI allocation.  Two women conceived again in the first 4 months postpartum, both non-hormonal contraceptive users.
Women using the etonogestrel implant and those using non-hormonal contraceptives demonstrate similar degrees of postpartum weight loss.   The etonogestrel implant placed shortly after delivery does not appear to affect postpartum weight loss in overweight and obese women by 6 months postpartum.  This current study provides a basis for future controlled studies. If findings are confirmed, the rate of use of the ENG-implant in this vulnerable population of postpartum women should increase.