Effects of nifedipine on fetal pulmonary blood flow in preterm labor

Abstract

Objective To determine the effect of nifedipine on the fetal pulmonary system by acceleration/ejection time ratio of the fetal main pulmonary artery Doppler waveform. Methods This prospective study was conducted in a high-risk pregnancy clinic with pregnant women who required nifedipine treatment to prevent preterm labor between 24 and 34 weeks of gestation. An ultrasound examination that included measurements of the acceleration time (AT), ejection time (ET), and AT/ET ratio (PATET) were performed before and 48 h after the first nifedipine dose. Results Forty-three pregnant women were included in this study. AT and PATET found higher in the after nifedipine group when compared with before nifedipine group. When the ET parameters were compared, no differences were detected between the groups. Conclusion Nifedipine increases fetal pulmonary blood flow which appears to increase AT and PATET on Doppler parameters in pregnant women with preterm labor after 48h treatment.