Poster Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2015

Human Fetal Kidney Volume in Gestational Diabetes (#118)

Stacey Hokke 1 , Bethany Carr 2 , Victor G Puelles 1 , Peter Coombs 3 4 , Carolyn C Allan 5 6 , Euan M Wallace 5 6 , John F Bertram 1 , Luise Cullen-McEwen 1
  1. Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria
  2. Maternal and Child Health Services, Monash Medical Centre, Monash Health, Clayton, Victoria
  3. Diagnostic Imaging, Monash Medical Centre, Monash Health, Clayton, Victoria
  4. Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria
  5. Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria
  6. Hudson Institute of Medical Research, Clayton, Victoria

Aim: To assess, using data from obstetric ultrasonography, whether gestational diabetes (GDM) affects human fetal kidney volume as a measure of renal sufficiency.

Background: GDM is associated with adverse perinatal outcomes and long-term health risks for the offspring. However, studies examining fetal kidney development in human pregnancies complicated by maternal glucose intolerance are lacking.

Methods: A prospective cohort study was undertaken at Monash Medical Centre, Monash Health. Fetal biometry and kidney size were measured by obstetric ultrasound at 32-34 weeks in in a multi-ethnic group of women identified with or without GDM by routine testing (n=42 non-GDM, n=47 GDM). Women diagnosed with GDM where treated with diet and exercise and a third received insulin therapy. Fetal kidney volume, as a measure of renal sufficiency, was calculated using the approximation of a prolate ellipsoid.

Results: Maternal age and body mass index were similar in non-GDM and GDM women. Estimated fetal weight (EFW) at 32-34 weeks (P=0.002) and birth weight (P=0.01) were lower in GDM pregnancies. Spectral Doppler fetal middle cerebral artery pulsatility index (P=0.03) and amniotic fluid index (P=0.03) were slightly lower in GDM pregnancies but within the normal range. There was no difference in fetal kidney volume (P=0.90) or kidney volume adjusted for EFW (P=0.11). Fetal kidney length was greater in GDM pregnancies following adjustment for EFW (P<0.0001).

Conclusions: GDM is an increasingly common complication that is typically associated with neonatal macrosomia. Unexpectedly, lower EFW and birth weight were reported in the GDM cohort. The mechanism for this is not clear however a possible explanation is low-level placental dysfunction. These preliminary data indicate that, despite this, fetal kidney growth is normal in GDM. This study is ongoing and assessment of renal function in babies born to women with GDM will commence in late 2015.