Cardiac Abnormalities in Fetuses of Diabetic Mothers

Abstract

Summary T he consequences of uncontrolled diabetes mellitus (DM) during pregnancy are severe to both mother and fetus. The risk of congenital malformations among infants of diabetic mothers is related to the diabetic control these mothers receive. Maternal DM affects the fetal heart both structurally and functionally. In early gestation, it has a teratogenic effect causing primary cardiogenesis defects. In late gestation, it causes a unique form of hypertrophic cardiomyopathy. Given the increased risk of congenital abnormalities among infants of diabetic mothers, an appropriate biochemical and ultrasonographic screening process and a detailed evaluation of fetal cardiac structure should be offered to all pregnant women with diabetes. The timing of development of the myocardial changes in the fetus of the diabetic mother has been well demonstrated by fetal echocardiography. Fetal echocardiographic investigations suggest the onset of hypertrophy occurs even before 20 weeks of gestation with documentation of increased ventricular septal thickening relative to fetuses in non diabetic pregnancies. Fructosamines are keto-amines formed by a non-enzymatic reaction between glucose and a protein (60-70% of which is glycosylated with albumin in serum), depending upon the severity and the duration of the hyperglycemia. Therefore, serum fructosamine directly reflects the dynamics of blood glucose concentration and correlates significantly with the mean plasma glucose levels from the preceding 1 to 3 weeks. The current study included 42 pregnant mothers that were classified into: 30 diabetic mothers (group I) and 12 non-diabetic mothers (group II). Pregnant diabetics were futhur classified according to Hb A1c levels into (12 cases controlled diabetic mothers (group Ia) (Hb A1c < 7) and (18 cases uncontrolled diabetics (group Ib) (Hb A1c ≥ 7) and according to serum fructosamine into (11 cases controlled diabetic mothers (group Ic)(200-285µmol/L) and 19 cases uncontrolled diabetic mothers (group Id)(S. fructosmine > 285µmol/L). Gestational ages ranged from 22 weeks to 28 weeks at the time of examination with a mean of gestational age 24.4 ± 1.6(weeks). Which is a well-established and excellent timing for echocardiographic findings and outcome (Gembruch, 1997; Carvalho, 2001). All patients were subjected to the following: - Full history taking laying stress on age, duration of illness, symptoms suggestive of start of diabetic complications as well as obstetric history. • Gestational age • History of diabetes before pregnancy • History of antidiabetic medical treatment (insulin or oral antidiabetic treatment) before or during pregnancy • Other associated risk factors (hypertension, renal impairment, etc) • History of previous fetal death • History of previous baby with congenital heart disease or hypertrophic myopathy. - Laboratory investigations including: • Complete blood count, kidney function test (serum creatinine) • Random blood sugar • Last Hb A1c levels (chromatographic method) • Serum fructosamine levels (Colorimetric assay technique) - Fetal echocardiography using standards views (four chamber, five chamber, three vessels and tracheal views) to exclude or verify the presence of congenital heart diseases. No statistically significant difference was found between group I and group II and between controlled and uncontrolled diabetic pregnants regards maternalageand number of birth. Laboratory investigation of all studied groups showed a statistically significant increase in HbA1c and serum fructosamine levelsin group I compared to group II.(P value < 0.001). And also a statistically significant increase was found in serum fructosamine levels in group Ib compared to group Ia (P value < 0.001), and astatistically significant increase was found in HbA1cingroup Idcompared togroup Ic.(P value < 0.001). Fetal echocardiography data revealed that increase in pulmonary vein pulsatility index (PVPI) in group I compared to group II and in group Ib compared to group Ia and in group Id compared to group Ic (p: <0.001,<0.001,<0.001) respectively. No statistically significant difference was found between group I and group II and between controlled and uncontrolled diabetic pregnants regards interventricular septal thickness (IVST), lateral (Em, Am, Em/Am), septal (Em, Am, Em/Am). All patients showed a statistically significant positive correlation was found between interventricular septal thickness (IVST) and gestational age (GA)(P:0.007).