University of Southern Denmark Maternal pre-pregnancy obesity and timing of puberty in sons and daughters

Background: In many countries, an increased prevalence of obesity in pregnancy has coincided with a declining pubertal age. We aimed to explore the potential effect of maternal pre-pregnancy overweight and obesity on timing of puberty in sons and daughters. Methods: Between 2012 and 2018, 15 819 of 22 439 invited children from the Danish National Birth Cohort, born 2000–03, provided half-yearly information from the age of 11 years on the pubertal milestones: Tanner stages, voice break, first ejaculation, menarche, acne and axillary hair. We estimated adjusted mean monthly differences (with 95% confidence intervals) in age at attaining the pubertal milestones for children exposed to maternal pre-pregnancy obesity [body mass index (BMI) 30.0 kg/m] or overweight (BMI 25.0 to 29.9 kg/m) with normal weight (BMI 18.5 to 24.9 kg/m) as reference. In mediation analysis, we explored whether childhood BMI at age 7 years mediated the associations. Results: Maternal pre-pregnancy obesity was associated with earlier age at attaining most pubertal milestones in sons, and pre-pregnancy overweight and obesity were associated with earlier age at attaining all pubertal milestones in daughters. When combining all pubertal milestones, pre-pregnancy obesity [sons: 1.5 ( 2.5, 0.4) months; daughters: 3.2 ( 4.2, 2.1) months] and overweight [daughters only: 2.6 ( 3.3, 1.8) months] were associated with earlier timing of puberty. The associations in sons were completely mediated by higher childhood BMI and partly so in daughters. VC The Author(s) 2019. Published by Oxford University Press on behalf of the International Epidemiological Association. 1684 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com International Journal of Epidemiology, 2019, 1684–1694 doi: 10.1093/ije/dyz125 Advance Access Publication Date: 25 June 2019