- Increased BMI and hypothyroidism show a strong, consistent association with gestational diabetes mellitus (GDM).
- Findings suggest women with known thyroid disease should be offered GDM screening earlier in pregnancy.
Why this matters
- GDM is associated with increased risks of short- and long-term maternal and infant morbidity.
- Umbrella review of 30 papers with data from 61 different meta-analyses.
- Significant effect defined as P-6, >1000 cases, between-study heterogeneity not large (I2
- “Highly suggestive” results were >1000 cases, significant effect at P−6, and nominally statistically significant effect in the largest study.
- Funding: None.
- After applying credibility criteria, low vs normal BMI (kg/m2), BMI ~30-35 vs normal weight, BMI >35 vs normal weight, and hypothyroidism (all types) presented convincing evidence for GDM association.
- Risk factors presenting highly suggestive evidence for GDM include: prepregnancy BMI (continuous variable), overweight vs normal BMI, BMI >30 vs normal weight, overweight vs nonoverweight, obese vs nonobese, snoring, sleep-disordered breathing, PCOS, and family history of diabetes.
- Some studies may have been omitted.
- All observational data.
- Possible selective reporting in some studies.