Objective: We described the metabolic phenotypes of early-onset gestational diabetes mellitus (GDM) and their association with adverse pregnancy outcomes.
Methods: This study is a secondary analysis of the vitamin D and lifestyle intervention for GDM prevention (DALI) trial. In pregnant women (BMI ≥29kg/m2) with early GDM (<20 weeks), insulin sensitivity and secretion were estimated using the homeostasis model assessment for insulin resistance (HOMA-IR) and Stumvoll first phase indices, respectively. Dichotomizing the median values in women with normal glucose tolerance (NGT), GDM women were classified into 3 groups: GDM-R (insulin resistance alone), GDM-S (secretion impairment alone), and GDM-B (a combination of both). GDM was treated according to local protocols.
Results: In the 902 women included, the GDM rate was 27.7% before 20 weeks. Compared with women in the NGT group (n = 652), women in the GDM-R group (n = 145) had higher BMI and fasting and post-load glucose values and insulin levels. Women in this group were at greater risk of having large for gestational age babies (adjusted odds ratio [aOR] = 2.98 [1.47–6.07]) and cesarean section (aOR = 2.59 [1.39–4.81]) than those in the NGT group. Women in the GDM-B group (n = 62) experienced the highest fasting and 2-hour glucose values, and their neonates were more likely to develop small for gestational age (aOR = 3.44 [1.19–9.98]) and hyperbilirubinemia (aOR = 4.97 [1.69–14.63]) than those of women in the NGT group. Pregnancy outcomes were similar in both GDM-S (n = 37) and NGT groups.
Conclusion: Pregnancy outcomes among women with an early diagnosis of GDM differed dependent upon their underlying pathophysiology.