Early Diabetes Treatment is Associated with Improved Outcomes in Pregnant Women with a First Antenatal HbA1c of 41–46 Mmol/mol

Background It is unclear whether early treatment of women with a first antenatal HbA1c of 41-46 mmol/mol improves pregnancy outcomes. Our Hospital Guideline (HG) recommends early treatment, but the New Zealand GDM Guideline (NG) recommends lifestyle advice and a 75 g OGTT at 24-28 weeks' gestation. Aims The aim of this study was to compare, at a single centre, pregnancy outcomes in women who were treated before 24 weeks (HG group) with women who were managed according to the NG. Our hypothesis was that earlier treatment was associated with lower rates of pre-eclampsia and preterm birth. Materials and Methods Women who had a first antenatal HbA1c of 41-46 mmol/mol between January 2016 and December 2019 and delivered at our institution before August 2020 were included. Baseline characteristics, management of GDM and pregnancy outcomes were collected. Univariable and multivariable analyses were performed. Results There were 141 women in the HG group and 67 women in the NG group. The NG group had fewer Indian/Chinese/Other Asian women (P = 0.004) and BMI was higher (P = 0.05). Women in the NG group, compared with the HG group, had more infants with a customised birthweight >90(th) centile (19.4% vs 7.8%, P = 0.014). In addition, after adjusting for ethnicity and BMI, women in the NG group had higher rates of pre-eclampsia (ORa (95th CI), 3.7 (1.1-13.3), P = 0.04) and preterm birth (2.8 (1.1-7.0), P = 0.03). Conclusions Management according to our Hospital Guideline, compared with the National GDM Guideline, was associated with lower rates of pre-eclampsia, preterm birth and infants with a customised birthweight >90(th) centile.