Prediction of recurrent gestational diabetes mellitus: a retrospective cohort study.

Background: Women after gestational diabetes mellitus (GDM) are at increased risk for development of GDM recurrence. It was the aim of our study to evaluate factors for prediction of risk of recurrence.

Methods: In this retrospective cohort study we included 159 women with GDM and a subsequent pregnancy. Putative risk factors for GDM recurrence were analyzed by logistic regression models. Results were compared to a cohort of age-matched women without GDM as controls (n = 318).

Results: The overall risk of GDM recurrence was 72.3% (115/159). Risk factors of recurrence were a body mass index (BMI) ≥ 30 kg/m before the index pregnancy (odds ratio (OR) 2.8 [95% CI 1.3-6.2], p = 0,008), a BMI ≥ 25 kg/m before the subsequent pregnancy (OR 2.7 [95% CI 1.3-5.8]. p = 0.008), a positive family history (OR 4.3 [95% CI 1.2-15.4], p = 0.016) and insulin treatment during the index pregnancy (OR 2.3 [95% CI 1.1-4.6], p = 0.023). Delivery by caesarean section (index pregnancy) was of borderline significance (OR 2.2 [95% CI 0.9-5.2], p = 0.069). Interpregnancy weight gain, excessive weight gain during the index pregnancy and fetal outcome where not predictive for GDM recurrence. Neonates after GDM revealed a higher frequency of transfer to intensive care unit compared to healthy controls (OR 2.3 [95% CI 1.1-4.6], p = 0.0225). The best combined risk model for prediction of GDM recurrence including positive family history and a BMI ≥ 25 kg/m before the subsequent pregnancy revealed moderate test characteristics (positive likelihood ratio 7.8 [95% CI 1.1-54.7] and negative likelihood ratio 0.7 [95% CI 0.6-0.9]) with a positive predictive value of 96.6% in our cohort.

Conclusions: A positive family history of diabetes mellitus in combination with overweight or obesity were strongly associated with recurrence of a GDM in the subsequent pregnancy. Normalization of the pregravid BMI should be an effective approach for reducing the risk of GDM recurrence.