Meeting paper
PCOGS papers
Utilization of noninvasive prenatal testing: impact on referrals for diagnostic testing

Presented at the 83rd annual meeting of the Pacific Coast Obstetrical and Gynecological Society, Marana, AZ, Oct. 22-26, 2014.
https://doi.org/10.1016/j.ajog.2015.04.005Get rights and content

Objective

Since the introduction of noninvasive prenatal testing (NIPT), a marked decrease in prenatal diagnostic testing (chorionic villus sampling [CVS] and amniocentesis) has been observed with unknown potential effects on genetic diagnosis of these pregnancies. The purpose of this study was to understand the impact of NIPT on genetics counseling referrals, diagnostic testing with CVS/amniocentesis, and appropriate use of NIPT.

Study Design

A retrospective cohort study was performed on all women referred for genetic counseling and prenatal testing during the 2 years preceding the introduction of NIPT (pre-NIPT) and 2 years following (post-NIPT). The primary outcome was the difference in the number of women referred for genetic counseling and prenatal diagnosis during the pre-NIPT period compared with the post-NIPT period. The secondary outcome was the difference in the number of women referred who were not considered candidates for NIPT between the 2 study periods.

Results

There was a statistically significant reduction in the number of referrals for genetic counseling and diagnostic testing in the post-NIPT compared with the pre-NIPT period (2824 vs 3944, P = .001), a reduction of 28.4%. During the post-NIPT period there was a significant reduction in referrals of women who would not be candidates for NIPT (467 pre-NIPT vs 285 post-NIPT, P = .043). In women who had diagnostic testing with CVS during the study period, 32.4% of the aneuploidies identified would not have been detected by NIPT.

Conclusion

There was a significant reduction in the number of patients referred for genetic counseling and prenatal diagnosis following the introduction of NIPT. In addition, there was a significant reduction in the number of patients referred for counseling and testing who would not be candidates for NIPT. This suggests that an increasing number of potential patients are being offered NIPT screening instead of diagnostic testing, including those at risk for fetal single gene disorders and aneuploidies not detectable by NIPT, potentially leading to misdiagnosis.

Section snippets

Materials and Methods

A retrospective cohort study using a natural experiment pre-NIPT and post-NIPT was conducted to compare a group of women referred to the Cedars-Sinai Prenatal Diagnosis Center for genetic counseling and prenatal testing from Jan. 1, 2010, through Dec. 31, 2011 (pre-NIPT) with women referred from Jan. 1, 2012, through Dec. 31, 2013 (post-NIPT). The primary outcome for the study was the difference in the number of women referred to our center for genetic counseling and prenatal diagnosis during

Results

During the pre-NIPT period, 3944 women were referred for counseling and testing. In the post-NIPT period, 2824 women were referred for counseling and testing. This represents a significant decrease in referrals of 28.4% (P = .001). A comparison between the study groups is shown in Table 1. There was a statistically significant decrease in the referrals for advanced maternal age (89.3% vs 79.4%; P = .001). No differences in referral rate were observed for follow-up of a positive first-trimester

Comment

Between the pre-NIPT and post-NIPT study periods, we observed a 28% decrease in the overall number of patients referred for genetic counseling and prenatal diagnosis. There was a statistically significant decrease in the referrals for advanced maternal age. We also found that there was a significant reduction in the number of patients who would not be candidates for NIPT due to the presence of multiple gestations, vanishing twin, and risk for either single gene disorders or unbalanced

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  • Cited by (0)

    J.W. is a member of the advisory panel for Natera Inc, San Carlos, CA. The remaining authors report no conflict of interest.

    Cite this article as: Williams J, Rad S, Beauchamp S, et al. Utilization of noninvasive prenatal testing: impact on referrals for diagnostic testing. Am J Obstet Gynecol 2015;213:102.e1-6.

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