TYPE 1 DIABETES IN PREGNANCY; INFLUENCES ON MOTHER AND FETUS

The fetal cerebro-placental ratio in diabetic pregnancies is influenced more by the umbilical artery rather than middle cerebral artery pulsatility index

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).

STUDY DESIGN

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.

Ductus venosus blood flow velocity waveform in diabetic pregnancies

OBJECTIVE

Maternal diabetes during pregnancy is associated with congenital cardiac malformations and hypertrophic cardiomyopathy. Blood flow in the ductus venosus (DV) has been postulated to reflect cardiac function. The aim of our study was to investigate if diabetic pregnancies exhibit abnormal DV hemodynamics, hence indicating changes in fetal cardiac function.

METHODS

The pulsatility index of the DV (DV-PI) was analyzed retrospectively in 142 diabetic patients and compared to previously published DV-PI reference values from a non-diabetic low-risk population. DV values were then correlated with maternal glycosylated hemoglobin (HbA1c).

RESULTS

DV-PI was significantly higher in pregnancies complicated by either pre-existing insulin-dependent (DM) or gestational diabetes when compared with normal reference values. Increased DV-PI values were still evident in both diabetic groups when neonates that were small-for-gestational age and neonates with pathological umbilical blood flow pattern were excluded from the analysis. In DM pregnancies a statistically significant correlation was found between DV-PI and maternal HbA1c.

CONCLUSION

Diabetic pregnancies exhibit increased DV-PI values when compared to a normal low-risk pregnant population, possibly indicating a fetal cardiac effect.