AIMS/INTRODUCTION: The aim of the present study was to examine the associations of pregestational body mass index (BMI) and gestational weight change with birthweight for gestational age in Japanese mothers with gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

We retrospectively examined the clinical and laboratory characteristics of 101 mothers with GDM (pregestational BMI 24.7 ± 5.8 kg/m ; maternal age at delivery 34.7 ± 5.1 years; gestational age 38.5 ± 1.4 weeks) at a single center from January 2011 to December 2016.

RESULTS

Gestational weight changes were 6.22 ± 5.39 kg, and infant birthweights were 2,987.3 ± 393.6 g. Multivariable analysis showed that, in all mothers, pregestational BMI and gestational weight change were positively associated with infant birthweight (P < 0.001 and P = 0.007, respectively). Pregestational BMI, but not gestational weight change, was positively associated with infant birthweight (P = 0.007) in 31 mothers with GDM who had pregestational BMI ≥25 kg/m ; in 68 mothers with GDM who had pregestational BMI 18.5-24.9 kg/m , only gestational weight gain was positively associated with infant birthweight (P = 0.039). Two mothers had pregestational BMI <18.5 kg/m . No statistically significant interactions of pregestational BMI with gestational weight change were found (P = 0.158).

CONCLUSIONS

In mothers with GDM, pregestational BMI ≥25 kg/m and excessive gestational weight gain were significantly associated with increased infant birthweight. A prospective multicenter clinical study enrolling a larger number of mothers with GDM will be required to verify the effects of adequately controlling pregestational and gestational weights on infant birthweight for gestational age.