Advanced maternal age (AMA) and 75 g oGTT glucose levels are pedictors for insulin therapy in women with gestational diabetes (GDM).

Objectives: Gestational diabetes (GDM) is a common complication during pregnancy that is strongly associated with adverse fetal and maternal outcomes. Advanced maternal age (≥35 years) is a known risk factor for GDM. Studies advocate that GDM comprises distinctive metabolic entities, suggesting an individualized approach based on early pregnancy characteristics (such as 75 g oGTT values, maternal age, obstetric history).

Methods: The oGTT blood glucose levels of 1,664 women were categorized into isolated fasting hyperglycemia (GDM-IFH), isolated postprandial hyperglycemia (GDM-IPH) and combined hyperglycemia (GDM-CH), using the levels of the fasting, 1 h and 2 h values after glucose application. These three subtypes were analysed regarding baseline characteristics as well as fetal and maternal outcome in the context of maternal age.

Results: This analysis reveals that the 75 g oGTT levels and maternal age can distinguish metabolic phenotypes in women with GDM. The overall rate of insulin therapy required was higher in women from the GDM-CH group and increased with maternal age (31.7 %, 38.2 %, <35 years, ≥35-39 years respectively, vs. total insulin rate 22.3 %, p-value <0.001). Women ≥35 years displayed a significantly higher caesarean delivery (CD) rate (<35 years 34.6 %, 38.4 %, 41.1 % vs. ≥35 years 54.8 %, 47.6 %, 46.5 %, GDM-IFH, GDM-IPH, GDM-CH respectively, p-value <0.001).

Conclusions: Women with fasting hyperglycemia, especially those with combined hyperglycemia and advanced maternal age (AMA) display a higher risk for unfavorable perinatal outcome. A categorization based on oGTT values and maternal age, as well as other characteristics can facilitate a basis for clinical risk stratification. Women at risk should receive an individualized and intensified perinatal care as well as interventional therapies.