ATLANTIC DIP: Despite insulin therapy in women with IADPSG diagnosed GDM, desired pregnancy outcomes are still not achieved. What are we missing?

Delia Bogdanet, Aoife Egan, Catriona Reddin, Breda Kirwan, Louise Carmody, Fidelma Dunne

To assess if pregnancy outcomes for women with GDM treated with insulin (GDM-I) are comparable to outcomes for women with GDM treated with medical nutritional therapy (MNT) (GDM -M). This retrospective cohort study included 752 women with GDM-I and 567 women with GDM-M. Maternal and foetal outcomes were examined. Women with GDM-I had a greater risk of polyhydramnios (aOR 2.33, 95%CI 1.31-4.14) and were more likely to deliver by caesarean section (CS) (aOR 1.67, 95%CI 1.25-2.23). Their offspring had higher rates of macrosomia (22.2% vs 12.7%; p<0.01), large for gestational age (LGA) (19.7% vs 12.5%; p<0.01) and were more likely to require neonatal intensive care unit (NICU) admission (aOR 4.88. 95%CI 3.54- 6.73). There was no difference between the groups in rates of pre-eclampsia (PET), pregnancy-induced hypertension (PIH), infant mortality, congenital malformations, neonatal hypoglycaemia, prematurity and rates of small for gestational age (SGA). GDM-I and GDM-M mothers have similar rates of maternal medical morbidities. Despite this, the rate of delivery by CS remains greater, possibly driven by physician choice for elective intervention in the GDM-I group. Despite insulin therapy, offspring of GDM-I mothers experience higher rates of macrosomia, LGA and NICU admissions. This may be related to the higher baseline risk profile in GDM-I women, to sub-optimal glycaemic control, excessive gestational weight gain (GWG) or higher baseline BMI of the mother. Addressing baseline maternal BMI, limiting excessive GWG and tightening glycaemic control in GDM-I women may translate to better pregnancy outcomes.