Normal fetal cardiac flow velocity waveforms between 11 and 16 weeks of gestation.

Abstract

The purpose of our study was to determine the nature of fetal cardiac flow velocity waveforms in late-first- and early-second-trimester pregnancies. Eighty-eight normal pregnancies were studied according to a cross-sectional study design between 11 and 16 weeks of gestation. Fetal waveforms at the semilunar level showed a gestational age-related rise in peak systolic flow velocities, with significantly higher velocities in the ascending aorta. Similarly, a gestational age-related rise in peak-E wave (early diastolic filling) and peak-A wave (atrial contraction) velocity was observed at the atrioventricular level, with significantly higher velocities at the tricuspid valve level. Compared with late gestation, these data suggest a reduced ventricular compliance or ventricular relaxation rate and a raised cardiac afterload in the normally developing late-first- and early-second-trimester fetus.