Geographical Distribution of Chorion as a Selection Factor for a Chorionic Villus Sampling Approach

Abstract

INTRODUCTION: The objective of this study was to define a simple protocol for selection of chorionic villus sampling (CVS) route (abdominal compared with transcervical) based on the ultrasound-detected location of chorion. METHODS: All patients who underwent CVS at Nassau University Medical Center, NY Downtown Hospital, and Moscow University School of Medicine, January 12, 2007, to June 1, 2013, were included. Patients with anterior fundal and located chorion had transabdominal CVS; patients with posterior or low-lying chorion had transcervical CVS. All procedures were performed under ultrasound guidance. Patients in whom access to chorion was judged to be difficult or two procedures failed to obtain a specimen were referred to a tertiary care center. Number of attempts per procedure, number of successful procedures, and pregnancy loss rates were analyzed. RESULTS: One thousand forty patients were included. Seventy-two (6.9%) were referred to the tertiary care center. Six hundred eighteen underwent transabdominal and 350 transcervical CVS. Six hundred eleven (98.9%) of transabdominal and 341 (97.4%) of transcervical CVS samples were diagnostic. Tissue samples were obtained from the first pass of the needle or catheter in 588 (95.1%) of transabdominal procedures and 301 (86%) of transcervical CVS. Overall pregnancy loss rate within 3 weeks after the procedure was 0.42. One hundred thirty patients were lost to follow-up. CONCLUSION: Tailoring transabdominal compared with transcervical route of CVS access to the geographical location of chorion in the uterine cavity resulted in diagnostic accuracy of the procedure superior to the historical controls with fewer needle or catheter insertion attempts per procedure and improved success in specimen retrieval. The miscarriage rate with tailored CVS is comparable to the historical controls.