"The pill" suppresses adolescent bone growth, no matter the estrogen dose

Brajic et al examine the benefits and risks of adolescent use of continuous or cyclic combined hormonal contraceptives (CHC). Long-acting reversible contraceptive agents, such as implants and intrauterine devices, are ideally first-line methods for adolescents because of improved adherence and bone safety. However, a prospective, population-based, 2-year observational study of Canadian adolescents aged 16-19 years showed that those who used CHC had decreased gains in femoral bone mineral density compared with those who did not use CHC. Loss of bone mineral density on CHC was unrelated to dose of ethinyl estradiol. Earlier data had already shown the lack of a dose effect from CHC estrogen on bone; patients on 20-35 μg ethinyl estradiol CHC formulations all had suppressed markers of bone remodelling. Recent meta-analysis comparing adolescents who did and did not use CHC also showed impaired accrual of bone mineral density among CHC users across a wide range of doses.