Increased fetal cardiac natriuretic peptide secretion in type-1 diabetic pregnancies.

Background: We hypothesised that human fetal cardiac natriuretic peptide secretion is increased in type-1 diabetic pregnancies with normal placental hemodynamics, and this increase is related to the first trimester maternal glycemic control.

Methods: Thirty-two neonates of type-1 diabetic mothers and 60 neonates born after uncomplicated pregnancy and labour (control group) were included in this study. Diabetic pregnancies were divided into two subgroups based on the first trimester HbA1c value. Group 1 pregnancies (n =22) had a good glycemic control (HbA1c <7.5%) and Group 2 pregnancies (n =10) had a poor glycemic control (HbA1c > or =7.5%). At delivery, an umbilical artery (UA) blood sample was obtained for assessment of N-terminal peptide of proatrial (NT-proANP) and proB-type (NT-proBNP) natriuretic peptide levels. In diabetic pregnancies, each fetus had normal UA Doppler velocimetry for gestational age.

Results: The newborn UA NT-proANP and NT-proBNP concentrations were significantly higher in type-1 diabetic pregnancies than in the control group. Group 2 fetuses with poor glycemic control showed significantly higher UA NT-proANP levels than Group 1 fetuses. UA NT-proANP levels correlated significantly with maternal HbA1c values in the first, second and third trimesters, while UA NT-proBNP levels did not correlate with maternal HbA1c values.

Conclusions: In type-1 diabetic pregnancies, fetal cardiac natriuretic peptide secretion is increased, even in the presence of good glycemic control and normal placental hemodynamics. In addition, fetal NT-proANP levels are already related to maternal glycemic control in the first trimester of pregnancy.