Transvaginal Doppler study of uterine artery blood flow in in vitro fertilization-embryo transfer cycles

Objective: To verify whether uterine artery impedance, measured as pulsatility index and resistance index is related to the outcome of in IVF-ET cycles. Design: Prospective study of infertile women participating in an IVF-ET program. Setting: University Hospital. Patients: Two hundred women (24 to 40 years of age), who had one to three good quality embryos transferred to the uterus after a standardized IVF cycle. Intervention: Transvaginal color Doppler and a blood sample on the day of ET. Main Outcome Measures: Uterine artery pulsatility index and resistance index, endometrial thickness, serum E(2) and P concentrations, clinical pregnancy rate (PR). Results: Pulsatility indices and resistance indices were lower in conception (2.45 +/- 0.54 and 0.85 +/- 0.04, respectively) than in nonconception cycles (2.66 +/- 0.39 and 0.87 +/- 0.04, respectively), although the overlap of the values is considerable. Overall PR was 35% per ET, and it decreased significantly when pulsatility index was >3.0 (15%) and resistance index > 0.92 (13%), being lowest when pulsatility index was >3.3 and resistance index > 0.95 (10%). Such a high impedance was detected in 9% of nonconception cycles. Conclusion: In IVF-ET cycles the uterus is likely to be unreceptive when uterine artery pulsatility index is >3.3 and resistance index > 0.95 before ET, but this occurs only in 9% of the cycles.