Bewley, Susan Jane; (1990) Doppler investigation of placental blood flow in the second trimester: a screening study for pre-eclampsia and growth retardation. Doctoral thesis (M.D), UCL (University College London).

Text Doppler_investigation_of_place.pdf Download (12MB)

Abstract

In a cross-sectional study of 977 women recruited from the booking ultrasound clinic at 16-24 weeks gestation, the resistance index (RI) in the uteroplacental circulation and umbilical artery were measured by continuous wave Doppler ultrasound. Reference ranges for these indices were constructed and their relation to maternal social factors and morphometry established. Pregnancies with high values had a higher incidence of pre-eclampsia, abruptio, small-for-gestational age babies, and fetal wastage. Cut-off levels for sensitivity and specificity for the prediction of complications were produced. Additional studies were made. The RI varied with uterine site and placental location so a new methodology for insonation was developed. Confirmation of the vessel studied was supplied by colour flow mapping and in-vivo studies at laparotomy. The intra-observer error was established. The feasibility of the screening study and methodology were tested in a pilot study of 21 women. The hospital computer provided pregnancy and delivery details in 832 cases. The reliability of the data was assessed in a comparative study of 50 cases. In the remaining 145 cases information was collected after a series of searches including 2 postal requests to GPs and subjects. Follow-up was successful in 96.5% of cases. In 237 cases where pregnancy complications were recorded the medical notes were retrieved and 3 independent observers coded the diagnoses. The changes in RI with gestation observed in the cross-sectional study were confirmed in a longitudinal study of 33 women from 16-40 weeks. A postpartum study of 21 women suggested the restitution of the uteroplacental circulation to its non-pregnant state does not occur immediately after delivery. Predictions of pregnancy complications by Doppler parameters were compared to one another and to an obstetric risk score. Furthermore, in 183 women, the maternal serum AFP, HPL, BHCG, PAPP-A, SPl and PP12 were poorer predictors than Doppler ultrasound.

Download activity - last month

Export as CSVJSONXML

Download activity - last 12 months

Export as XMLJSONCSV

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item