Influence of Overweight and Obesity on Bone Remodeling during Pregnancy

Background The prevalence of maternal overweight and obesity during pregnancy continues to increase. Less is known on how this can influence bone health. The aim of this study was to evaluate the association between body mass index (BMI) and bone remodeling (BR) during pregnancy. Material and Methods We evaluated 579 pregnant women participants of the ELEMENT cohort in Mexico City. We used mixed effects models to analyze the association between baseline BMI (normal, overweight, obesity) and trimester-specific measurements of urinary N-telopeptides (NTx, nM BCE/mM creatinine), radius axial quantitative bone ultrasonography speed-of-sound z-score (Z-SOS) in a subsample of 429 women and bone specific alkaline phosphatase in plasma in a subsample of 143 women. Models were adjusted for age, number of pregnancies, pregnancy weight gain, breastfeeding history, calcium, phosphorus, magnesium, and vitamin D intakes. Results 39% of women were overweight and 15% were obese in the first trimester of pregnancy. Compared to normal weight women, overweight and obese women had lower Z-SOS (b=-0.28, 95%CI: -0.49, -0.08 and b=-0.57, 95%CI: -0.87, -0.27, respectively), this difference seemed to be greater between 25 and 35 weeks of gestation. Conclusions Our study found an attenuated bone speed of sound among overweight and obese pregnant women relative to their normal weight counterparts indicating more active bone remodeling. We provide evidence of women’s skeletal health in a gestational-obesogenic setting, follow-up of these women will provide insight to the long-term relation between pregnancy and midlife bone health.