Uterine artery Doppler perfusion in the first and second pregnancies

To compare blood perfusion expressed as pulsatility index (PI) and 'notching' of the left and right uterine arteries measured in the same woman in her first and second pregnancies.

Data from 1102 women's uterine perfusion in their first and second pregnancies were evaluated. Bilateral data, PI and early diastolic notch in both pregnancies were collected. A notch and a PI > or = 1 were deemed to be pathologic. Statistical mean and standard deviation together with the frequency of pathological uterine perfusion in the first and second pregnancies were compared (t-test, chi 2-test).

PI values did not differ significantly in the first and second pregnancies whereas there was a small but marked difference in the right uterine artery compared to the left. Early diastolic notch behaved differently, being more frequently found in the first pregnancy. This discrepancy was highly significant. However in subsequent pregnancies a notch was found more frequently on the left than on the right side. Women with pathologic flow patterns in the first pregnancy were significantly more likely to develop pathologic flow patterns in their second pregnancy.

Although uterine perfusion in the same woman is similar in the first and second pregnancies, 'notching' appears much more frequently in the first pregnancy reflecting the fact that the decidual embedding of the trophoblast is less problematic in the second pregnancy. Nevertheless the subgroup with an early diastolic notch in their first pregnancy is four times more likely to develop a notch in a second pregnancy.