Repeat Late GDM Testing and Cesarean Delivery Rates

This will be a prospective randomized control trial to determine if re-testing for gestational diabetes in the third trimester after an ultrasound measurement of estimated fetal weight (EFW) or abdominal circumference greater than 90%ile decreases cesarean delivery rate, and to evaluate the optimal method of re-testing. Pregnant women will be recruited with gestational age between 30 weeks and 36 weeks gestation with an ultrasound that demonstrates a fetus with either estimated fetal weight (EFW) >90%, abdominal circumference (AC)>90% or both. They will be randomized into two groups: Group 1 will undergo a repeat glucose tolerance test (GTT) with blinded continuous glucose monitor (CGM) and group 2 will have no intervention. Participants in group 1 will receive nutrition counseling as this would be standard in patients at high risk for gestational diabetes.

The primary outcome is cesarean delivery. Labor course, complications, and delivery/neonatal data will be obtained.

Inclusion criteria

• Gestational age 30 weeks 0 days and 36 weeks 6 days
• Ultrasound with estimated fetal weight or abdominal circumference greater than 90th%ile
• Age 18-50 years old.

Exclusion criteria

• Previously diagnosed gestational diabetes or pre-gestational diabetes
• Multiple gestation
• Previous cesarean delivery
• Any condition precluding vaginal delivery (placenta previa/placenta accreta spectrum disorders, vasa previa, prior uterine surgery with contraindication to vaginal delivery)
• Suboptimal dating (based on US >22wk gestation)
• Contraindication to glucose tolerance test