First‐trimester umbilical vein blood flow in pregnancies with low serum pregnancy‐associated plasma protein‐A levels: an early predictor of fetal growth restriction

Objective To investigate umbilical vein blood flow (UVBF) during the first trimester in pregnancies with low serum pregnancy‐associated plasma protein‐A (PAPP‐A) levels and to relate umbilical vein (UV) diameter, time‐averaged maximum velocity (TAMXV) and UVBF values to the subsequent development of fetal intrauterine growth restriction (IUGR). Methods UVBF assessment was performed at 11 + 0 to 13 + 6 weeks' gestation in 102 singleton pregnancies with PAPP‐A concentrations of < 0.3 multiples of the median. UV diameter, UV‐TAMXV and UVBF were calculated and analyzed in relation to pregnancy outcome. Results Pregnancy outcomes were: 51 pregnancies with birth weight ≥ 10th centile (Group A), 30 pregnancies with birth weight < 10th centile with normal Doppler in the umbilical artery throughout gestation (Group B) and 21 pregnancies with birth weight < 10th centile and abnormal umbilical artery Doppler later in gestation (Group C). No differences were found in PAPP‐A levels between groups. Group C fetuses exhibited significantly lower values of UV‐TAMXV (z‐score − 1.99 SDs, t = 8.527, P ≤ 0.0001) and UVBF (z‐score − 0.97 SDs, t = 7.420, P ≤ 0.0001) in comparison with normal reference ranges, while no differences were found in Groups A or B. Conclusions Decreased UV‐TAMXV and UVBF at 11 + 0 to 13 + 6 weeks' gestation identify fetuses at risk of developing IUGR among pregnancies with low levels of PAPP‐A. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.