Decreased endovascular trophoblast invasion in first trimester pregnancies with high-resistance uterine artery Doppler indices

BACKGROUND: Defective trophoblastic invasion in early pregnancy is involved in the pathogenesis of pre-eclampsia. This study investigates the relationship between Doppler assessment of uterine artery resistance and endovascular trophoblastic invasion in the first trimester of pregnancy. METHODS: Patients undergoing termination of pregnancy for non-medical reasons were categorized as having a low- or high-resistance uterine artery blood flow pattern by transabdominal Doppler ultrasound. Products of conception were examined histologically with regard to the extent of decidual endovascular trophoblast invasion. RESULTS: There were 14 low-resistance and 17 high-resistance uterine artery blood flow pregnancies identified at 10-14 weeks of gestation. Normal intradecidual endovascular trophoblast invasion was identified with a similar frequency in both groups (P = 0.79). However, the proportion of decidual vessels with endovascular trophoblast invasion was significantly higher in the low-resistance pregnancies (49%) compared with the high-resistance ones (34%, P = 0.02). CONCLUSIONS: The findings of this study support the use of uterine artery Doppler investigation for the non-invasive assessment of trophoblast invasion in early pregnancy. Further studies are necessary to clarify the biological significance of these observations and their potential clinical applications.