Ultrasound detection rate of single umbilical artery in the first trimester of pregnancy.

Objective: To determine accuracy of first trimester detection of single umbilical artery (SUA).

Methods: The number of vessels in the umbilical cord was examined in a prospective cohort of 779 singleton, low-risk, unselected pregnancies, in the first (11-13 weeks) and second (17-24 weeks) trimesters, using both power and color Doppler and after delivery, by placental histopathologic exam. Concordance between first and second trimester findings to postnatal diagnoses was compared by calculating kappa coefficients.

Fetal tricuspid valve Doppler at 11-13 weeks and 6 days: reference values and reproducibility.

Objective: To determine normal blood flow velocities across the fetal tricuspid valve (TV) at 11-13 weeks and 6 days of gestation and to examine the reproducibility of these measurements.

Methods: A prospective study involving 166 normal singleton pregnancies examined at 11-13 weeks and 6 days was carried out. Descriptive analysis of E- and A-waves' maximum velocities, E/A ratio, duration of the cardiac cycle (C) and diastole (D) and D/C ratio were calculated.