The impact of pre-pregnancy body mass index on the risk of gestational diabetes

Abstract

Objective: To evaluate the effect of pre-pregnancy body mass index (BMI) on the risk of developing gestational diabetes mellitus (GDM) in a large unselected population. Methods: We performed a case control study using data collected in The Consortium on Safe Labor database. The association between BMI and GDM was evaluated both using BMI weight categories adopted by the National Institute of Health, and separately using BMI as a continuous variable. Multiple logistic regression analyses were used to evaluate the effects of BMI, age, ethnicity, parity, chronic hypertension and antenatal steroid use on the risk of GDM. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to approximate relative risks of GDM. A p value of <0.05 was considered significant. Results: After controlling for other factors, the risk of GDM increased with an increasing BMI across all weight categories. For each 1 kg/m² increase of BMI the OR of developing GDM was 1.08 (95% CI 1.08–1.09) and for each 5 kg/m² increase, the OR was 1.48 (95% CI 1.45–1.51). Conclusions: GDM is a multifactorial disorder and pre-pregnancy BMI plays an important role in that risk. Modest changes in pre-pregnancy BMI may decrease the risk of GDM substantially.

Keywords::

• Diabetes mellitus
• diagnosis
• obesity
• pregnancy complications

Acknowledgements

Statistical support for this project was provided through the Medstar Health Research Institute, a component of the Georgetown-Howard Universities Center for Clinical and Translational Science.

Declaration of interest: (i) Creation of The Consortium on Safe Labor database was made possible by a grant funded by the NIH (NICHD, NIH, Contract No. HHSN267200603425C). (ii). Statistical support for this project was provided through the Medstar Health Research Institute, a component of the Georgetown-Howard Universities Center for Clinical and Translational Science and supported by Grant 1UL1RR031975 from the NCRR, a component of the National Institutes of Health (NIH). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.