Association Between Maternal Serum N-Terminal Pro-B-Type Natriuretic Peptide Level and Gestational Duration in Patients With Pulmonary Hypertension

Abstract Objective: To investigate the correlation between maternal serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and gestational duration in pregnant women with pulmonary hypertension (PH). Methods: The study included pregnant individuals with PH stemming from mitral valve stenosis and mitral valve regurgitation (post-capillary PH) or pulmonary arterial hypertension (pre-capillary PH) who were admitted to Guangdong Provincial People’s Hospital between January 1, 2014 and December 31, 2020. In this retrospective cohort study, maternal serum NT-proBNP levels during pregnancy, along with other clinical data, were obtained from structured electronic medical records. These data included gestational age at delivery, echocardiographic parameters, laboratory findings, gestational duration, delivery mode, and other relevant clinical variables. Univariate and multivariate regression analyses were conducted to assess the association between NT-proBNP levels and gestational duration. Adjustments were made for potential confounding factors, and curve fitting and threshold effect analysis were employed to identify tangent points. Furthermore, stratified analyses were performed based on tricuspid regurgitation velocity, maternal age, and parity. Results: A total of 64 patients with post-capillary PH and 74 patients with pre-capillary PH were included in this study. Among patients with post-capillary PH, the results of multivariate regression analysis indicated a significant association between maternal NT-proBNP levels and gestational duration (β = –0.03, 95% confidence interval (CI) –0.05 to 0.00, P = 0.02). The fitted curve demonstrated a negative correlation between maternal NT-proBNP levels and gestational duration, with a significant break point at 379.9 ng/L ( P < 0.05). In the post-capillary PH group, the stratified analysis revealed a regression coefficient of –0.05 (95% CI: –0.06 to –0.04, P = 0.001) in patients with a tricuspid regurgitation velocity >340 mm/s. For patients >35 years old, the regression coefficient was –0.03 (95% CI –0.06 to –0.01, P = 0.02). In multiparous women, the regression coefficient was –0.03 (95% CI –0.06 to 0.00, P = 0.03). Conclusion: In pregnant women with pulmonary hypertension, maternal NT-proBNP levels are associated with gestational duration particularly an increased risk of preterm labor.