Introduction: To assess the potential role of the fetal abdominal circumference measurement at the time of gestational diabetes mellitus(GDM)diagnosis as a predictor of LGA at delivery and adverse neonatal outcomes.
Methods: This is a retrospective cohort study of women diagnosed with GDM between 2010-2017.All women had a fetal growth scan within two weeks of GDM diagnosis.Patients were categorized according to fetal abdominal circumference (AC)characteristics: (1)AC ≥ 90th percentile, and (2)AC < 90th percentile. All percentiles were calculated according to Hadlock3 formula.Primary outcome was large for gestational age at delivery (defined as birth weight above the 90th percentile for gestational age). Secondary outcome included lifestyle modification failure, and neonatal complications as prolonged NICU stay (>48h), hypoglycemia,phototherapy due to hyperbilirubinemia, or respiratory complications (defined as RDS, transient tachypnea of the newborn, need for intubation).
Results: of the 883 eligible women, 154 (17.4%) had AC measurement ≥90th percentile upon GDM diagnosis. Mean gestational age at GDM diagnosis was not clinically significant between the groups. Women with fetal AC>90%tile tend to be older and heavier, with comparable gestational weight gain upon GDM diagnosis (Table 1). Fetal AC was strongly correlated to EFW,r=0.857; p<0.001, and moderately correlated with head circumference to AC (HC/AC ratio),r=-0.478; p<0.001.Women with fetal AC≥90th percentile at GDM diagnosis had significantly higher rates of LGA and lifestyle modification failure. Neonatal complications were comparable between the groups (Table 1).Logistic regression analysis adjusting for maternal age, pre-pregnancy BMI, gestational age at GDM diagnosis and neonatal sex revealed significant association between AC≥90thpercentile and LGA at delivery and pharmacotherapy requirement throughout the pregnancy (Table 2).Sub-analysis including women with fetal AC>90th percentile and EFW90th percentile and LGA (adjusted OR=2.07(95% C.I 1.04-4.13) but not with lifestyle modification failure.
Conclusion: Fetal abdominal circumference upon GDM diagnosis is a strong predictor for adverse outcome. This suggests the need for targeted interventions in this group.
Eran Ashwal– Fellow mfm, Mount Sinai Hospital
Nir Melamed– MFM Specialist, Sunnybrook Health Sciences Centre, University of Toronto
Jon Barrett– Chief of Maternal-Fetal Medicine at Sunnybrook Health Sciences Centre, Sunnybrook Health Sciences Centre, University of Toronto
mira Persaud– research, University of Ottawa
Taylor Reddi– research, York University
beth Murray-Davis– phd, university of Toronto
Sarah McDonald– Professor, Canada Research Chair, Departments of Obstetrics & Gynecology, Radiology, and Health Research Methods, Evidence, & Impact, McMaster University
howard Berger– associated professor, university of Toronto