Intrauterine exposure to oral contraceptives marginally affects pubertal timing
Children exposed to oral contraceptives (OCs) early in pregnancy tend to start puberty and achieve some pubertal milestones at an earlier age, although the magnitude of effect is small and imprecise, a study has found.
The analysis included 15,800 children born during 2000–2003 into the Danish National Birth Cohort, grouped according to maternal use of combined OC pills or progestin-only pills reported around gestational week 17: no exposure (reference; n=11,828), exposure 4 months before conception (n=3,518) and exposure in early pregnancy (n=454). Children self-assessed pubertal status by completing web-based questionnaires from 11 years and biannually throughout puberty.
Intrauterine exposure to OCs showed a tendency toward slightly earlier mean age of achieving some individual pubertal milestones and overall pubertal timing. Specific milestones included voice break (months, −3.8; 95 percent CI, −6.5 to −1.0) and first ejaculation (months, −2.9, −5.9 to 0.1) in boys, and menarche (months, −1.9, −4.0 to 0.3) and Tanner breast stages in girls. The mean age difference for overall pubertal timing was −1.4 months (−3.3 to 0.4) in boys and −0.9 months (−2.7 to 1.0) in girls.
OC exposure prior to conception was not associated with pubertal timing. Furthermore, prepubertal body mass index did not exhibit a mediating effect.
Additional studies are needed, particularly those that that can distinguish between formulations of OCs and timing of exposure in foetal life, owing to the study limitations and rarity of the exposure, researchers said.