Risk of gestational diabetes mellitus in nulliparous women - Associations with early life body size and change in body mass index from childhood to adulthood.

Abstract Aims We examined whether a woman’s birthweight, childhood height, body mass index (BMI), and BMI changes from childhood to pregnancy were associated with risks of gestational diabetes mellitus (GDM). Methods We studied 13,031 women from the Copenhagen School Health Records Register born 1959-1996 with birthweight and measured anthropometric information at ages 7 and/or 13. The diagnosis of GDM (n=255) was obtained from a national health register. Risk ratios (RR) were estimated using log-linear binomial regression. Results Own birthweight and childhood height were inversely associated with GDM. Girls with overweight at age 7 had a higher risk of GDM than girls with normal-weight (RR: 1.79, 95% CI: 1.31, 2.47). Compared to women with normal-weight in childhood and adulthood, risks of GDM were higher in women who developed overweight from age 7 to pregnancy (RR: 4.62; 3.48, 6.14) or had overweight at both times (RR: 4.71; 3.24, 6.85). In women whose BMI normalized from age 7 to pregnancy the RR for GDM was 1.08 (0.47, 2.46). Conclusions Lower birthweight, shorter childhood height, and higher childhood BMI are associated with increased risks of GDM. Efforts to help girls maintain a normal BMI before pregnancy may be warranted to minimize risks of GDM.