Normal reference of cervical blood perfusion in pregnancy.

Objective: To develop normal reference of cervical blood perfusion in pregnancy by using 3D power Doppler-derived FMBV at 16 to 24 weeks gestation.

Material And Method: The present prospective cohort study recruited the normal singleton pregnant women at 16 to 24 weeks gestation who had antenatal care and midtrimester ultrasound screening at Ramathibodi Hospital between June and September 2012. Transvaginal ultrasound (TVU) measurements of cervical length (CL), cervical volume (CV), vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were performed.