Objective: The purpose of this study was to estimate spiral artery subchorionic flow at 8-11 gestational weeks (GW) by Doppler ultrasound and then to analyze these vessels in the decidua basalis using histologic, morphometric and immunohistochemical analyses.
Methods: Subchorionic spiral arteries were evaluated in 5 women scheduled for aspiration at 8-11 GW. Flow velocity waveforms were sought using color and pulsed Doppler, and the diastolic/systolic (D/S) index was calculated. Transcervical biopsy specimens and aspiration products were thoroughly examined to investigate the structure of the spiral artery at the implantation site using cytotrophoblastic and arterial smooth muscle cell immunohistochemical markers (anti-cytokeratin 7 and anti-actin monoclonal antibodies). Spiral artery cross-sectional inner areas were measured and compared with the D/S index in each case.
Results: Low-impedance pulsatile flow could be detected below the trophoblastic ring in all cases. Complete obstruction of a spiral artery lumen was never observed and cytotrophoblastic cells were incorporated into the vessel wall starting from the perivascular cuff.
Conclusion: Both techniques evidenced that decidual spiral arteries in the placental bed are not completely obstructed at 8-11 GW.
Copyright 2005 S. Karger AG, Basel.