ENG-releasing subdermal implants in postpartum teenagers - an open-label trial study protocol

Higher than expected adolescent pregnancy high rates continue globally, with repeated unplanned pregnancy (UP) in this age group is a public health problem. In Brazil, 16% of pregnancies occur in adolescents under 18 years old, with high maternal morbidity and mortality rates in this age group. Effective and safe contraception is required to reduce UP rates. The objective of our study is to evaluate acceptance of etonogestrel (ENG)-releasing subdermal contraceptive implant after childbirth, before discharge, as well as clinical performance up to one year after placement. Comparison between teenagers who opt for ENG-implant versus other contraceptive methods after childbirth will be also evaluated, specifically regarding UP, continuation and discontinuation rates and reasons, body composition, pelvic ultrasound characteristics and user satisfaction.

A non-randomized open-label trial will be conducted with teenagers after childbirth and followed up to one year at the Women's Hospital, University of Campinas (UNICAMP), Campinas, Brazil. The study group will consist of patients who accepted to use ENG-implant and placed before discharge. The comparison group will include adolescents who choose to use other contraceptive methods at the first postpartum visit (42 ± 3 days after childbirth). All women will follow-up at 40-60 days postpartum, as well as, at 6 and 12 months post-enrollment. Patient satisfaction, contraceptive effectiveness, reasons of discontinuation, continuation rate and body composition will be evaluated. Transvaginal ultrasound and electric bio impedance tests will be performed at all follow-up appointments. A 5% significance level was assumed, as well as, a sampling error (absolute) for 10% prevalence. The sample size was calculated at n = 100, obtaining an estimate of 50 to 70 adolescents who would accept the method offered, according to the prevalence and sample error assumed.

Long-acting reversible contraceptive (LARC) methods include subdermal implants and intrauterine contraceptives, are considered first line contraception for teenagers. Immediate postpartum use is a safe option, which significantly reduces rates of repeated UP and all the undesirable consequences inherent to this process.

This study was approved by the Ethics and Research Commission of UNICAMP (CAAE: 92869018.5.0000.5404) and the Brazilian Registry of Clinical Trials (REBEC): http://www.ensaiosclinicos.gov.br/rg/RBR-4z7bc6, (number 2.901.752).