Screening for placental insufficiency by transvaginal uterine artery Doppler at 22-24 weeks of gestation.

OBJECTIVE: To determine the value of routine transvaginal color Doppler assessment of the uterine arteries at 22-24 weeks of gestation in the prediction of placental insufficiency.

METHODS: Women with singleton pregnancies scheduled for routine ultrasound scans at 22-24 weeks were offered Doppler assessment of the uterine arteries by transvaginal ultrasound. The pulsatility index (PI) was obtained for each artery and the mean value was calculated. A mean PI >95th percentile was considered increased. Screening characteristics for predicting placental insufficiency, defined as preeclampsia, fetal growth restriction or intrauterine death, were calculated.

RESULTS: Doppler examination of the uterine arteries was carried out in 1,057 singleton pregnancies. The mean uterine artery PI was 1.03 and the 95th percentile was 1.55. In 54 cases (5.1%) the mean PI was >1.55 (screen-positive). In the study population there were 48 cases of preeclampsia (5.1%), 72 fetal growth restrictions (7.5%) and 7 intrauterine deaths (0.7%). The screen-positive group showed an incidence of 47.1% of combined adverse results. The relative risks after a positive screening test were 7.3 (CI 4.2-12.6) for pre-eclampsia, 3.9 (CI 2.3 - 6.6) for fetal growth restriction and 4.5 (CI 3.2-6.4) for overall placental insufficiency.

CONCLUSIONS: Uterine artery Doppler at 22-24 weeks identifies women at higher risk for the development of subsequent complications of placental insufficiency. This test could be used in combination with other markers to stratify the level of care offered in the third trimester of pregnancy.