JUGULAR VENOUS-BLOOD FLOW VELOCITY WAVE-FORMS IN HUMAN FETUSES BETWEEN 20 AND 42 WEEKS OF PREGNANCY

Background. The goal of the study was to measure the blood flow parame ters of the fetal internal jugular vein during the second half of norm al pregnancy using Doppler ultrasound. Methods. Jugular blood flow was analyzed in 95 normal singleton fetuses between 20 and 42 weeks gesta tion. Color and pulsed Doppler ultrasound was used to obtain jugular v enous waveforms at the level of the mid-neck. Peak velocities, ratios of velocities, and time-averaged maximum velocities were measured. Res ults. Jugular venous waveforms in healthy fetuses consist of three pha ses - the first forward peak occurs during ventricle systole; the seco nd forward peak occurs during early diastole and the third peak occurs during atrial contraction. Forty-eight percent of the fetuses demon s trated absent flow during atrial contraction; 32% of fetuses demonstra ted forward flow during atrial contraction and finally 20% of fetuses demonstrated flow reversal during atrial contraction. Conclusions. The reported jugular venous profile may serve as a foundation for future studies of jugular blood flow in high risk fetuses.