Oral Presentation Australasian Diabetes in Pregnancy Society and Society of Obstetric Medicine Australia and New Zealand Joint Scientific Meeting 2021

Maternal predictors of small for gestational age infants in gestational diabetes mellitus pregnancies. (#13)

Sarah Chalak 1 , Tang Wong 1 2 3 , Robyn Barnes 1 4 , Jeff R Flack 1 2 3
  1. Department of Diabetes and Endocrinology, Bankstown-Lidcombe Hospital SWSLHD, Sydney, NSW, Australia
  2. School of Medicine, Western Sydney University, Sydney, NSW, Australia
  3. Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
  4. University of Newcastle, Newcastle, NSW, Australia

Background: Gestational diabetes (GDM) management reduces the risk of large for gestational age infants and neonatal hypoglycaemia. Maternal risk factors for small for gestational age (SGA) within GDM populations are conflicting.

Aim: To evaluate maternal predictors for SGA in GDM pregnancies in a multiethnic GDM cohort.

Methods: Deidentified prospectively collected data were analysed from our database for singleton births in GDM women diagnosed by IADPSG criteria between years 2016-2020 at Bankstown-Lidcombe Hospital. Management included diet, with initiation of insulin if optimal targets were not achieved (fasting BGL <5.3 mmol/L; 1-hour post-prandial BGL <7.4 mmol/L; 2-hour post-prandial BGL <7.0 mmol/L.). SGA was defined as <10th centile.

Maternal characteristics assessed included: pre-pregnancy BMI, parity, weight gain by initial clinic visit, including insufficient weight gain based on Institute of Medicine recommendations, total pregnancy weight gain , ethnicity, early GDM diagnosis, FBGL on OGTT and use of insulin therapy. Pregnancy outcomes including caesarean section, early delivery (<37/40), neonatal hypoglycaemia and jaundice were assessed in SGA infants. Covariates significant on univariate analyses (p<0.05) were used for backward-stepwise logistic regression.

Results:

1735 GDM pregnancies were included in this analysis. Overall SGA prevalence in our cohort was 8.4%. Multivariable analysis identified insufficient weight gain at GDM presentation (aOR 1.42; 95% CI 1.02-1.97) and non-Middle Eastern ethnicity as independent positive predictors for SGA (aOR 1.66; 95% CI 1.07-2.56). Use of insulin therapy (aOR 0.55; 95% CI 0.39-0.79) was associated with a lower rate of SGA. Other assessed variables were not significant risk factors for SGA following multivariable analysis. There was more pre-term deliveries (13.1vs5.5% p<0.001) but no significant differences in caesarean section rate or other outcomes in SGA neonates.

Conclusions: Insufficient weight gain at initial GDM assessment was a risk factor for SGA. Women of Middle Eastern background had a significantly lower rate of SGA.