Postpartum weight loss in overweight and obese women using the etonogestrel subdermal implant: a pilot study

To compare weight loss during the first 6months postpartum in overweight and obese women using the etonogestrel implant, placed in the immediate postpartum period, with that of controls using nonhormonal contraception, utilizing a pilot design.

Pilot, prospective cohort study. Analysis groups were divided by body mass index (overweight: 25-29.9kg/m²; Class I Obesity: 30-34.5kg/m²; Class II Obesity: 35-39.9kg/m²) and grouped by use of etonogestrel implant or nonhormonal contraception for all outcomes. Primary outcome was the proportion of women in each group returning to pregravid weight by 6months postpartum. Secondary outcomes included waist circumference, motivation to lose weight, eating habits, physical activity, feasibility of study procedures and assessment of recruitment potential in the first 6months postpartum.

A total of 127 women enrolled between June 2014 and August 2015. Fifty-seven chose the etonogestrel implant for immediate postpartum contraception while 70 chose nonhormonal contraceptives. Six months after delivery, about half of women in each group returned to within 1.5 kg of pregravid weight (42% etonogestrel [ENG]-implant vs. 67% nonhormonal methods, p=.19). Retention rates were high with over 75% of total study population providing study data at 6months. Two nonhormonal contraceptive users conceived in the first 4months postpartum.

No statistical difference in percentage return to pregravid weight was detected between groups, but data suggest that a somewhat lower proportion of implant users lost weight at 6months. Rapid recruitment, high retention and marked acceptance of immediate ENG implant use demonstrate feasibility for a larger, adequately powered trial.

Immediate postpartum insertion of the ENG implant is safe and effective. Study findings suggest modest interference in overweight and obese women's ability to lose gestational weight. If future research demonstrates no statistical difference, increased uptake in immediate implant use should occur in most women, including those who are overweight or obese.