The effects of pre‐pregnancy BMI and maternal factors on the timing of adiposity rebound in offspring

Objective To assess the effect of pre‐pregnancy body mass index (BMI), gestational weight gain (GWG), and other maternal factors on the timing of adiposity rebound (AR). Methods In this study, 594 mothers (mothers who do not have diabetes and not underweight) from the longitudinal Growth and Obesity Chilean Cohort Study self‐reported their weights at the beginning and end of their pregnancies, and their heights were measured. Pre‐pregnancy BMI was categorized as normal weight, overweight, or obesity, and GWG was assessed according to Institute of Medicine guidelines. For children, weight and height measurements from 0 to 3 years were retrieved from records, and they were measured from age 4 to 7 years. BMI curves from 0 to 7 years were used to estimate the age at AR, which was categorized as early (7 years). The associations between pre‐pregnancy BMI and GWG and early AR were tested using logistic regression models. Results In total, 33% of the mothers had excess pre‐pregnancy weight, 31.2% exceeded Institute of Medicine recommendations, and 45% of children had early AR. The pre‐pregnancy BMI and parity were associated with earlier AR (OR = 1.07, 95% CI = 1.02‐1.11; OR = 0.86; 95% CI = 0.74‐0.99, respectively), but GWG was unrelated. Conclusions These results suggest that preventive strategies for promoting normal pre‐pregnancy BMI, especially in women's first pregnancies, could delay the timing of AR, with protective metabolic effects on offspring.