Hemoglobin A1c in Pregestational Diabetic Gravidas and the Risk of Congenital Heart Disease in the Fetus

Abstract

This study aimed to determine whether poor glycemic control in early pregnancy is associated with an increased risk of congenital heart disease (CHD) for infants of women with preexisting diabetes. A retrospective review examined two tertiary care centers of diabetic pregnancies that recorded early hemoglobin A1c (HbA1c) values (<20 weeks). The incidence of prenatally diagnosed CHD was calculated and stratified by HbA1c level. Poor glycemic control was defined as an HbA1c level of 8.5 % or higher. Fetal echocardiography was used to identify fetuses that resulted in infants with suspected CHD. Neonatal echocardiograms and pathology reports were reviewed for confirmation of the diagnosis. Of 535 patients, 30 (5.6 %) delivered an infant with confirmed CHD. Among the patients with poor glycemic control, 8.3 % (n = 17) delivered an infant with CHD, whereas 3.9 % (n = 13) of those with an HbA1c level lower than 8.5 % delivered an infant with CHD (p = 0.03). Poor glycemic control in early pregnancy is associated with an increased risk of CHD in offspring. The incidence of CHD in patients with adequate glycemic control still is sufficiently high to justify routine fetal echocardiography for all gravidas with preexisting diabetes regardless of HbA1c level.

Diabetes and Congenital Heart Defects

“…12–14 Some studies suggest that the excess risk can be eliminated with optimal diabetes management prior to and during early pregnancy. 8,13,15–17 …”

Obstetric Management of a Pregnant With Type I Diabetes and Poor Metabolic Control - A Case Report

“…The most common cardiac anomalies are conotruncals and defects of the interventricular septum [10]. Usually they are presented in a moderate, asymptomatic and transient form, however, congestive cardiomyopathy may occur.…”

“…Usually they are presented in a moderate, asymptomatic and transient form, however, congestive cardiomyopathy may occur. These changes appear more frequently in fetuses of pregnant women with poor metabolic control [10].…”

“…Its receptors have maximum expression between 19-25 weeks. Thus, excessive fetal growth may become apparent for 26-28 weeks, which is why it is recommended to evaluate early growth [10]. The term macrosomia refers to a fetus with a greater than usual weight (fetal weight greater than Pc90) considering gestational age.…”

Inhibition of Cardiomyogenesis in Embryocarcinoma Cells Induced by Long-Term High Level of Glucose

“…To date, hyperglycemia is considered to be a primary teratogen affecting organ development. Some retrospective reviews of diabetic pregnancies in human reported that poor glycemic control in early pregnancy is associated with increased risk of heart defects in offspring; the incidence of CHD in PGDM patients with a level of hemoglobin A1c (HbA1c) above 8.5% was almost three times higher than the incidence observed in patient with HbA1c levels lower than 8.5% [6,7]. Furthermore, fetal glucose concentration depends on fetal glucose uptake.…”