Background: To identify relevant factors predicting the need for insulin therapy in women with gestational diabetes mellitus (GDM) and secondly to determine a potential 'low- risk' diet-treated group who are likely to have good pregnancy outcomes.
Methods: A retrospective analysis between 2011-2014. Multivariable backward stepwise logistic regression was used to identify the predictors of the need for insulin therapy. To identify a 'low-risk' diet-treated group, the group was stratified according to pregnancy complications. Diet-treated women with indications for induction in secondary care were excluded.
Results: A total of 820 GDM women were included, 360 (44%) women required additional insulin therapy. The factors predicting the need for insulin therapy were: previous GDM, family history of diabetes, a previous infant weighing ≥ 4500 gram, Middle-East/North-African descent, multiparity, pre-gestational BMI ≥ 30 kg/m2, and an increased fasting glucose level ≥ 5.5 mmol/l (OR 6.03;CI 3.56-10.22) and two-hour glucose level ≥ 9.4 mmol/l after a 75-gram oral glucose tolerance test at GDM diagnosis. In total 125 (54%) women treated with diet only had pregnancy complications. Primiparity and higher weight gain during pregnancy were the best predictors for complications (predictive probability 0.586 and 0.603).
Conclusion: In this GDM population we found various relevant factors predicting the need for insulin therapy. A fasting glucose level ≥ 5.5 mmol/l at GDM diagnosis was by far the strongest predictor. Women with GDM who had good glycaemic control on diet only with a higher parity and less weight gain had a lower risk for pregnancy complications.