Tight glycemic targets in GDM reduce LGA births and cesarean rates but increase insulin use

This single-center, open-label randomized controlled trial enrolled 650 women with gestational diabetes mellitus (singleton pregnancies, 12-31 weeks' gestation), with 626 (96.3%) providing primary outcome data. Participants were assigned to tight glycemic targets (fasting <5.1 mmol/L, 1-hour postprandial <7.0 mmol/L) or less tight targets (fasting <5.3 mmol/L, postprandial <7.8 mmol/L). The primary outcome was incidence of large-for-gestational-age infants.

The tight-target group had a significantly lower incidence of LGA infants (19.2% vs 26.5%; adjusted relative risk 0.61; 95% CI 0.42-0.89; p=0.010). Cesarean delivery rates were also lower (23% vs 29.9%; aRR 0.63; p=0.012), and gestational weight gain was reduced (10.1 kg vs 10.7 kg; p=0.006). However, insulin use was higher in the tight-target group (32.6% vs 21.6%; aRR 1.67; p=0.005).

Safety data showed serious complications were low and comparable between groups. Maternal hypoglycemia rates were also low and comparable. The study did not report long-term outcomes for mothers or infants, quality of life measures, or cost-effectiveness.

This intention-to-treat analysis from a single-center RCT suggests tighter glycemic control may reduce some adverse perinatal outcomes but increases the need for insulin therapy. The open-label design and lack of long-term data limit definitive conclusions about clinical implementation.