Oral or Poster Presentation
Concurrent Session 2B - Maternal Fetal Medicine
Introduction: In non-pregnant samples, weight increases are associated with advanced biological aging, as measured by the epigenetic clock. During pregnancy and the postpartum period, however, weight change is a relatively normative process, and it is not known if changes in weight during this period also predicts differences in epigenetic clocks. The purpose of this study was to examine the effects of weight change during pregnancy and the postpartum period on GrimAge, a novel epigenetic clock index.
Methods: A pilot sample of 35 women were recruited from Los Angeles, CA, as part of the Healthy Babies Before Birth Study. Height and weight measures, for body mass index (BMI) calculation, were obtained at 8-16 weeks gestation, 30-36 weeks gestation, 6-weeks and 1-year post-birth. Change in BMI during pregnancy and after-birth follow-up were calculated. Whole blood samples for epigenetic assays were obtained at 8-16 weeks gestation and one-year post-birth. GrimAge was calculated using an online calculator. Covariates were assay batch, race/ethnicity, marital status, education, pre-pregnancy BMI and parity. Linear regression models were used to test associations between pregnancy and after-birth BMI change and after-birth GrimAge and change in GrimAge between pregnancy and one-year after-birth.
Results: Independent of covariates, increases in BMI during pregnancy predicted lower GrimAge one-year after-birth, b(SE)=-1.35(.507), p=.013. Increases in BMI between 6-weeks and one-year after-birth predicted higher GrimAge one-year after-birth, b(SE)=.950(.202), p<.001. Controlling for pregnancy GrimAge, increases in BMI after-birth also predicted increasing GrimAge between pregnancy and one-year after-birth, b(SE)=.407(.117), p=.002. Pregnancy BMI change, however, did not predict GrimAge change, p=.675.
Conclusion: Weight gain during the first year after-birth could accelerate biological aging, as indexed by GrimAge. In contrast, weight increases during pregnancy could be associated with lower biological age one-year after birth. These findings have implications for understanding how weight change during pregnancy and during the first-year after-birth impact biological aging in women.