Impact of chorionic villus sampling volume on time to result and pregnancy management.

Objective: To evaluate the association between low-volume chorionic villus sampling (CVS) and delay in patient care.

Methods: This is a retrospective cohort study of patients who underwent CVS from 8/19/2019 to 12/31/2022 in a single center. The exposure was low-volume CVS, defined as less than 15 mg of sample. The primary outcome of delay in patient care, was a composite of need for repeat procedure, delay in karyotype results ≥14 days, and ≥14 days to time of pregnancy termination. Secondary outcomes included change in lab protocol and canceled fluorescence hybridization (FISH) tests.

Results: There were 305 patients included with 113 (37%) with low-volume CVS. The primary outcome of delay in patient care occurred more often in the low-volume group compared to the high-volume group (23.9% vs 10.4% OR 2.70 95% CI 1.43-5.09). This association persisted in the adjusted models after adjusting for significant covariates. However, the individual outcome of delay to pregnancy termination was not different between the groups, even with controlling for covariates (14.2% vs 8.9% OR 1.70 95% CI 0.82-3.51).

Conclusion: Low-volume CVS was associated with an increased of delay in genetic testing results but did not increase the time to pregnancy termination in patients who opted for this outcome.