Fetal cardiac natriuretic peptides are increased in type I diabetic pregnancies

PREGNANCIES ANNA GIRSEN, KAARIN MAKIKALLLIO, MINNA ALA-KOPSALA, OLLI VUOLTEENAHO, JUHA RASANEN, University of Oulu, Obstetrics and Gynecology, Oulu, Finland, Oulu University Hospital, Oulu, Finland, University of Oulu, Dept of Physiology, Oulu, Finland OBJECTIVE: Up to 40% of newborns born to women with type 1 diabetes have echocardiographic signs of cardiomyopathy with cardiac enlargement and asymmetric septal hypertrophy. Recent studies have shown that atrial (ANP) and B-type natriuretic peptides (BNP) have antihypertrophic and antifibrotic effects. We hypothesized that fetal cardiac ANP and BNP secretions are increased in fetuses of type I diabetic mothers. STUDY DESIGN: A total of 24 neonates of type I diabetic mothers were included in the study. The control group consisted of 60 neonates born after uncomplicated pregnancy and labor. Diabetic pregnancies were divided into two subgroups based on the first trimester HbA1c value. Group 1 pregnancies (n=6) were considered to have an optimal glycemic control (HbA1c !6.2%), and group 2 pregnancies (n=18) to have a suboptimal glycemic control (HbA1c iÝ6.2%). In each diabetic pregnancy, the umbilical artery (UA) blood velocity waveform pattern was normal for gestational age. Newborn UA Nterminal peptide of proANP (NT-proANP) and NT-proBNP levels were assessed by specific radioimmunoassay. RESULTS: The newborn UA NT-proBNP and NT-proANP concentrations were higher (p!0.001) in diabetic pregnancies (327pmol/L (66-2335) and 1478pmol/L (259-3435)) than in the control group (176pmol/L (49-414) and 1029pmol/L (114-2357)). No differences were found in UA pH, pO2, pCO2 or base excess values at birth or in Apgar scores and birth weights between the two groups. No significant differences were found in newborn NT-proBNP and NT-proANP levels between diabetic pregnancies with optimal (277pmol/ L(185-1197) and 1584pmol/L(962-1909)) and suboptimal (404pmol/L(662335) and 1383pmol/L(259-3435)) glycemic control. No correlation was found between cardiac natriuretic peptides and maternal mean HbA1c value, or HbA1c values in 1st, 2nd and 3rd trimesters. CONCLUSION: Fetal ANP and BNP secretions are increased in type I diabetic pregnancies. Our results suggest that a rise in the secretion of cardiac natriuretic peptides is not related to glycemic control during pregnancy.