Preterm delivery and elevated maternal total vascular resistance: signs of suboptimal cardiovascular adaptation to pregnancy?

OBJECTIVE: To evaluate the maternal hemodynamic profile in women with a diagnosis of threatened preterm delivery (TPD) in order to understand the possible pathophysiologic mechanism leading to an increased lifetime risk for future cardiovascular disease. METHODS: Patients with a diagnosis of TPD were enrolled and assessed using a non-invasive method (USCOM® ) for the determination of hemodynamic parameters. Vaginal and rectal swabs were taken, cervical length, blood inflammatory indices, fetal blood-vessel Doppler velocimetry were measured and gestational age at the time of delivery and neonatal outcomes were noted. RESULTS: A total of 68 patients were enrolled and included in the analysis. The population was divided into two groups according to total vascular resistance (TVR): Group A with a TVR of ≤ 1000 dynes × s/cm5 (n = 48) and Group B with a TVR of > 1000 dynes × s/cm5 (n = 20). C-reactive protein (CRP) was higher in Group B than in Group A, suggesting a systemic inflammation status. Group B delivered earlier (32 + 4 weeks vs 38 + 2 weeks; P < 0.01) and neonatal outcome was worse than in Group A. Significantly lower values of cardiac output, stroke volume, peak velocity of flow, velocity time integral, minute distance, stroke volume index, cardiac index, stroke work, cardiac power, inotropy index and potential-to-kinetic energy ratio were observed in Group B than in Group A. CONCLUSIONS: Women with a diagnosis of TPD showing TVR values of > 1000 dynes × s/cm5 and elevated levels of CRP are at high risk of preterm delivery. An impaired maternal cardiovascular adaptation during pregnancy in these patients might suggest a possible higher risk for subsequent future cardiovascular disease. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.