878 Can maternal-fetal medicine fellows safely perform chorionic villus sampling procedures in ongoing pregnancies?

Abstract

Obtaining hands on experience in chorionic villus sampling (CVS) can be challenging for MFM trainees. Our protocol allows fellows who have met established criteria to perform CVS under direct supervision in consenting patients with fetal cystic hygroma (CH). The objective of this study was to evaluate the safety of CVS procedures performed by fellows in ongoing pregnancies. This is a retrospective cohort study of patients who had CVS performed from 6/2013 – 12/2019 at a single academic medical center for the indication of CH. Data on clinician training level (attending vs. fellow), karyotype results, number of passes, and approach (transcervical vs. transabdominal) were obtained from hospital records. Outcomes at 2-week follow up were also collected (spontaneous loss within 2 weeks, elective termination within 2 weeks, and ongoing pregnancy rates at 2 weeks). Statistics were performed with chi squared analyses to compare procedural data and 2 week outcomes. 406 CVS were performed during the study time period, 92 of which were performed for CH. 90 had 2-week follow up data available and were included in analysis (n=27 by attendings; n=63 by fellows). All 90 had adequate samples for analysis. 4 losses occurred within 2 weeks of CVS; all had abnormal karyotypes. When comparing CVS outcomes by attendings vs. fellows, there was no difference in the proportion of abnormal karyotypes (17/27 (63.0%) vs. 39/63 (61.9%), p=0.92), elective termination rate within 2 weeks (11/27 (40.7%) vs. 23/63 (36.5%), p=0.70), spontaneous loss rate within 2 weeks (2/27 (7.4%) vs. 2/63 (3.2%), p=0.37), procedures requiring >1 pass (1/27 (3.7%) vs. 9/63 (14.3%), p=0.14), or transcervical approach (15/27 (55.6%) vs. 31/63 (49.2%), p = 0.58). There was no difference in 2-week pregnancy loss rate following CVS performed by attendings vs. fellows. CVS may be safely performed by fellows under supervision.