Fetal Doppler flow measurements in the early second trimester: a correlation with fetal outcome.

In 31 women with a singleton pregnancy, abdominal duplex doppler examinations were performed at W16-W17, W26 (+/- 2 weeks) and W34 (+/- 2 weeks) in order to study the flow velocity wave (FVW) indices in the early second trimester and their predictive value for fetal outcome. 24 women with a normal pregnancy outcome were considered as the reference group. In the early second trimester, end-diastolic block occurs frequently at the 150 Hz thump filter setting (15/24 in the fetal descending aorta, 19/24 in the umbilical artery). At the 50 Hz filter setting, end diastolic block appeared in 1/24 cases in the aorta and in 2/24 cases in the umbilical artery. The finding did not persist throughout pregnancy. The flow-velocity indices in the early second trimester in the small-for-dates were comparable to the normal group. We conclude that high peripheral resistance is a common finding in the fetal circulation in early pregnancy. It is not predictive of subsequent growth retardation.