Ultrasonic predictors of macrosomia in gestational diabetes mellitus

BACKGROUND: The basis of early ultrasound (US) diagnosis of diabetic fetopathy (DF) in pregnant with gestational diabetes mellitus (GDM) is the forehanded detection of macrosomia, especially its asymmetric forms. In pregnant with GDM on a diet therapy, the detection of macrosomia may be an indication for starting the insulin therapy. In pregnant with hyperglycemia due to mutation in the glucokinase gene (GCK), US fetal growth dynamics helps to assume the fetal genotype, as well as to stratify the risks of insulin therapy. AIM: To determine the prognostic significance of asymmetric form of macrosomia and the value of the coefficients of proportionality for the diagnosis of DF in pregnant with GDM, including hyperglycemia due to mutation in the GCK gene. MATERIALS AND METHODS: US fetometry was performed in 95 pregnant with GDM (including 22 pregnant with hyperglycemia caused by mutation in the GCK gene) (main group) and 427 healthy pregnant women (control group). Estimated fetal weight, standard fetometric indicators and coefficients of proportionality were evaluated. Retrospective analysis of US predictors of macrosomia was carried out after evaluating the weight of the newborn and clarifying the signs of DF. RESULTS: In the group with GDM, 51 (53.7%) pregnant had children with phenotypic symptoms of DF, including macrosomia – 66,7% (34 children). We found statistically significant differences in fetal weight between the control group and the main group who gave birth to children with DF starting from 32 weeks. The coefficients of proportionality (femur length/abdominal circumference and the head circumference/abdominal circumference), characterizing the formation of the asymmetric macrosomia were significantly from 34 weeks (Р<0,05). CONCLUSION: The most effective predictive fetometric indicators for the diagnosis of fetal macrosomia are the dimensions of fetal abdomen and fetal weight > 90 percentile for gestational age. A specific sign of DF in pregnant with GDM is the asymmetric macrosomia. In pregnant with a mutation in the GCK gene, the tendency to macrosomia was revealed only in the absence of a mutation in the fetus, but insulin therapy in the presence of a similar mutation in fetus did not lead to a significant decrease in its percentile ranges

THE POSSIBILITIES TO DETERMINE FETAL MATURITY BY ULTRASOUND DIAGNOSTICS

Background: Extragenital disorders in a pregnant patient, as well as complications of pregnancy often necessitate preterm delivery, when the state of the fetus is one of the criteria determining terms and type of delivery. In connection with this, the physician faces the challenge of accurate assessment of fetal maturity. Aim: To identify ultrasound signs of functional fetal maturity. Materials and methods: 120 pregnant patients were assessed at 35 to 40 weeks of gestation. Beyond a standard fetometry, we assessed interhemispheric cerebellar size, the biggest size of the Beclard’s nucleus, the ratio of cortical to medullar substance of fetal adrenal glands (adrenal coefficient), the ration between ultrasound density of lungs, liver and ultrasound density of fetal urine (histogram analysis). Results: Up to 36 weeks of gestation, the interhemispheric cerebellar size was below 52 mm, starting from 37 weeks, above 53 mm and from week 40 on, above 58 mm. All newborns, which had their interhemispheric cerebellar size ≥ 53 mm antenatally, were assessed as being mature at birth (p < 0.05). All newborns, which had Beclard’s nucleus size ≥ 5 mm antenatally, were assessed as being mature at birth (p < 0.05). At 35–35.6 weeks of gestation, mean adrenal coefficients in all cases exceeded 1. Starting with full 36 weeks of gestation onwards, this parameter decreased to 0.94 and showed a steady decrease thereafter. There were no signs of functional immaturity or respiratory distress among newborns with antenatal adrenal coefficient of ≤ 0.99 (p < 0.05). The ratio between ultrasound density of lungs to ultrasound density of bladder contents increases up to 37 weeks of gestation and remains stable up to 40 weeks. The ratio of liver density to the same substrate is non-significantly lower due to lower ultrasound density of the liver itself. The ratio of ultrasound density of the lung to that of the liver up to 36 weeks was at least 1.41 and decreased from 37 to 40 weeks of gestation. Conclusion: The fetometric parameter of interhemispheric cerebellar size has the maximal correlation with the term of gestation and can serve as an indirect measure of functional fetal maturity. The size of Beclard’s nucleus and adrenal coefficient may serve as parameters that most clearly reflect fetal tissue maturity and allow predicting respiratory distress in a newborn. Linear sizes of the adrenal gland can not serve as a maturity criterion due to high error of measurements, depending on the level of section by its height (pyramidal form). Despite an increase of the ratio of ultrasound density of the lung to that of the liver with longer term of gestation, it cannot be considered a reliable parameter of lung maturity after 35 weeks of gestation