The Bernese gestational diabetes (GDM) project: Does pre-pregnancy BMI and weight gain in the first half of the pregnancy influence the development of GDM?
20 September 2018 (online)
The prevalence of gestational diabetes mellitus (GDM) is increasing worldwide and pre-existing metabolic disorders such as prediabetes or overweight/obesity are predisposing factors. The aim of the following study was to investigate if weight gain and pre-pregnancy BMI contributes negatively in groups stratified by first trimester glycosylate haemoglobin (HbA1c).
Prospectively recruited pregnant women with an HbA1c test at ≤14 weeks of gestation were included. Two groups were defined according to HbA1c: group 1 HbA1c value < 5.7%, and group 2 with HbA1c between 5.7 – 6.4%. In both groups pre-pregnancy body weight, BMI as well as weight gain until GDM screening were compared. Statistical significance was considered p-value < 0.05.
During the study period 668 women met inclusion criteria. Of those 636 were included in group 1, and 32 (4.7%) in group 2. The prevalence of GDM in our population was 14.6%. Group 2 had a higher pre-pregnancy BMI (group 2: 26.8 ± 6.4 kg/m2 vs. group 1: 23.3 ± 4.3 kg/m2; p = 0.02). Women who later developed GDM had a significant higher BMI in group 1 (GDM 25.57 ± 4.9 kg/m2 vs.22.9 ± 4.0 kg/m2, p = 0.0004) whereas BMI did not differ in group 2 (group 2: GDM 29.20 ± 7.9 kg/m2 vs.25 ± 4.7 kg/m2, p = 0.34). The weight gain until GDM screening between those with and without GDM did not differ (306 ± 168 g/week vs. 340 ± 156 g/week; p = 0.31).
In women with prediabetes the pre-pregnancy BMI is not different between those with and without GDM. On the contrary, in group 1 increased pre-pregnancy BMI seems to distinguish between women who develop GDM later on. Interestingly, weight gain before GDM diagnosis seems not to play an important role in GDM prevalence.