title: The fetal cerebro-placental ratio in diabetic pregnancies is influenced more by the umbilical artery rather than middle cerebral artery pulsatility index.
abstract: OBJECTIVE
  This study aimed to assess the relationship between the cerebro-placental ratio (CPR) and intrapartum and perinatal outcomes in pregnancies complicated by pre-existing insulin dependent diabetes (pT1DM) mellitus, pre-existing non-insulin dependent diabetes mellitus (pT2DM) and gestational diabetes mellitus (GDM).
  
  
  METHODS
  This was a retrospective cohort study of 1281 women with diabetes mellitus birthing at the Mater Mothers' Hospital in Brisbane between 2007 and 2015. The CPR in non-anomalous singleton fetuses was measured between 34+0 and 36+6 weeks gestation and compared between types of DM treatment groups and correlated with intrapartum and perinatal outcomes.
  
  
  RESULTS
  Of the study cohort, 9.7% (124/1281) had pT1DM, 5.3% (68/1281) had pT2DM and 85.0% (1089/1281) had GDM. Of women with pT2DM and GDM, 61.8% (42/68) and 28.9% (315/1089) respectively, required insulin during pregnancy. Women with pT1DM had an increased odds of having a CPR <5th centile (OR 3.73, 95%CI: 1.90-6.96, p=0.0001) or a CPR <10th centile (OR 3.01, 95% CI: 1.80-4.91, p<0.0001) respectively. The odds of a UA PI >90th centile (OR 2.69, 95% CI: 1.60-4.39, p=0.0001) was higher in the pT1DM cohort. There was however no significant difference in the mean MCA PI between the three groups. Stratification by CPR centiles (<10th centile vs. ≥10th centile) demonstrated a lower birth weight in the CPR <10th centile cohort for all DM categories. The proportion of neonates with birth weights <10th centile were higher in the CPR <10th centile cohort with the GDM cohort having an odds ratio of 8.28 (95% CI 4.22-16.13, p<0.0001) of this complication. The CPR <10th centile cohort also had a greater proportion of adverse composite neonatal outcome regardless of type of DM.
  
  
  CONCLUSIONS
  Regardless of the type of DM, a low CPR was associated with poorer neonatal outcomes. Women with pT1DM also had the highest mean UA PI and lowest mean CPR despite no difference in the mean MCA PI between the three groups.
authors.affiliation: Mater Research Institute, University of Queensland, Level 3 Aubigny Place, Raymond Terrace, South Brisbane, Queensland, QLD 4101, Australia; School of Medicine, The University of Queensland, Brisbane, Australia.
authors.forename: Anthea
authors.initials: A
authors.lastname: Gibbons
authors.affiliation: Mater Research Institute, University of Queensland, Level 3 Aubigny Place, Raymond Terrace, South Brisbane, Queensland, QLD 4101, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Flatley
authors.affiliation: Mater Research Institute, University of Queensland, Level 3 Aubigny Place, Raymond Terrace, South Brisbane, Queensland, QLD 4101, Australia; School of Medicine, The University of Queensland, Brisbane, Australia. Electronic address: sailesh.kumar@mater.uq.edu.au.
authors.forename: Sailesh
authors.initials: S
authors.lastname: Kumar
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000000981:diagnostic imaging*; D003924:Diabetes Mellitus, Type 2 / Q000000981:diagnostic imaging*; D016640:Diabetes, Gestational / Q000000981:diagnostic imaging*; D005260:Female; D005865:Gestational Age; D006801:Humans; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011254:Pregnancy in Diabetics / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Adverse perinatal outcome; Caesarean section; Cerebro-placental ratio; Diabetes mellitus; Fetal hypoxia; Pregnancy