Analysis of follow-up information and pregnancy outcomes of cell free DNA prenatal screening / 中华妇产科杂志

ABSTRACT

Objective:To evaluate the efficacy of cell free DNA (cf-DNA) screening in prenatal care by analyzing the follow-up information and pregnancy outcomes.Methods:All cf-DNA cases conducted in Women′s Hospital of Nanjing Medical University from August 2011 to December 2017 were enrolled. The general information of the pregnancies, cf-DNA results, confirmatory testing results, and the follow-up results were collected. The pregnancy outcomes were analyzed in cases with low risk cf-DNA results as well as with high risk results for common trisomies, which were trisomy 21 (T21), trisomy 18 (T18), and trisomy 13 (T13). The sensitivity, specificity, positive predictive value and negative predictive value of cf-DNA screening were calculated.Results:(1) A total of 43 615 cf-DNA cases were involved, with 44 cases (0.10%, 44/43 615) test failure results, 314 cases (0.72%, 314/43 571) high risk results for common trisomies and 43 257 cases (99.27%, 43 257/43 571) low risk results. (2) Among 277 cases (88.21%, 277/314) high risk cases were successfully followed up, and 228 cases (82.31%, 228/277) underwent invasive confirmatory prenatal diagnosis. In the low risk results, 36 826 cases (85.13%, 36 826/43 257) were successfully followed up, and 572 (1.55%, 572/36 826) cases were found to have adverse pregnancy outcomes, among which 4 false negative cf-DNA results were confirmed. (3) In the 37 103 successfully followed up cf-DNA cases, the sensitivity for T21, T18, T13 were calculated as 97.96%, 96.67% and 100.00%, respectively; the specificity for T21, T18, T13 were calculated as 99.96%, 99.95% and 99.95%, respectively. The positive predictive value for T21, T18, T13 were calculated as 90.57%, 63.04% and 17.39%, respectively. The negative predictive value for T21, T18, T13 were calculated as 99.99%, 99.98% and 100.00%.Conclusions:Cf-DNA is effective in detecting common trisomies, with a high sensitivity and specificity. However, the follow-up information revealed several potential limitations in current clinical practice, such as a number of cases with high risk results rejected invasive confirmatory testing, as well as the genetic diagnostic results for most low risk cases with an adverse pregnancy outcome aren′t obtained. Genetic counseling and the follow-up for all the cf-DNA cases should be emphasized in the future.