Association of Pre-Pregnancy Body Mass Index and Gestational Weight Gain with Neonatal Anogenital Distance in a Chinese Birth Cohort

Background This study aimed to investigate the associations of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with anogenital distance (AGD) among newborns. Methods The study included 556 mother-newborn pairs from the Jiashan birth cohort. AGD was measured as AGD AP (from the center of the anus to the anterior base of the penis, where the penile tissue meets the pubic bone) and AGD AS (from the center of the anus to the posterior base of the scrotum, where the skin changes from rugate to smooth) in males and AGD AC (from the center of the anus to the clitoris) and AGD AF (from the center of the anus to the posterior convergence of the fourchette) in females. Multiple linear regression models were used to estimate the associations of pre-pregnancy BMI and GWG, with AGD. Results After adjusting for pre-pregnancy BMI and other potential confounders, male newborns whose mothers had excessive GWG had shorter AGD AP than those whose mothers had normal GWG. Male newborns whose mothers had normal pre-pregnancy BMI and inadequate/excessive GWG had shorter AGD AP than the reference group where mothers had normal pre-pregnancy BMI and GWG in stratified analyses. Conclusion Gestational weight gain during pregnancy was associated with AGD in newborns in this birth cohort.