The influence of placental perfusion on birthweight in women with gestational diabetes

Abstract

Objective: To evaluate the influence of both uterine and umbilical arteries Doppler pulsatility indexes (PI) and metabolic control on birthweight in pregnant women with gestational diabetes mellitus.Methods: One hundred sixty-nine women with gestational diabetes were evaluated. Doppler measurements of umbilical artery and mean uterine arteries PI were recorded and the corresponding Z-score values by gestational age calculated. Maternal pregestational body mass index (BMI) and the levels of glycosylated hemoglobin were also recorded. The relationships between these studied variables and customised birthweight centiles according to sex and gestational age were analyzed using Spearman’s correlation coefficient and linear regression.Results: There was a significant correlation between birthweight centiles and Z-score values of the umbilical artery PI (r = −0.25, p = 0.001), but not with the Z-score values of the uterine artery PI (r = −0.12, p = 0.43). Third trimester maternal glycosylated hemoglobin was also positively correlated to birthweight (r = 0.29, p = 0.01). When using stepwise linear regression both maternal glycosylated hemoglobin and the Z-score of umbilical artery PI were included as independent variables in the predictive model of birthweight centile (p = 0.0002, p = 0.001 respectively, R2 = 0.27).Conclusions: Umbilical artery PI predicts birthweight in women with gestational diabetes. However, metabolic control is the only important determinant of fetal macrosomia in these mothers.