Retrospective analysis of the risk factors associated with failure in obtaining effective noninvasive prenatal test results and pregnancy outcomes: a case-control study

ABSTRACT

Objective

To explore the pregnancy outcomes of women who couldn't obtain effective results from noninvasive prenatal testing (NIPT) and examine the factors leading to test failure.

Methods

From April 2017 to December 2019, 120,041 pregnant women enrolled for voluntary NIPT. The case group comprised of 274 (274/120,041) women who failed to obtain effective NIPT results, and the control group (n = 540) was from the same population who obtained effective NIPT results and matched by age at a 1:2 ratio. Abnormal pregnancy rates between the two groups were analyzed using Chi-square analysis. NIPT failure risk factors were analyzed using logistic regression analysis.

Results

Logistic regression analysis showed that increased maternal age (OR = 0.988; 95% CI = 0.982–0.994), increased pregnancy age (OR = 0.989; 95%CI = 0.988–0.991), and decreased cell-free fetal DNA concentration (OR = 1.050; 95%CI = 1.043–1.058) were independent risk factors for NIPT failure. Fifteen cases showed fetus loss in cases of NIPT failure. There was a significant difference in abnormal pregnancy rate between the NIPT success and failure groups (χ2 = 50.943, P < 0.05).

Expert commentary

The specific interventions, guidance, and precautions are needed for pregnant women who have no effective NIPT results.

KEYWORDS:

• Noninvasive prenatal testing
• cell-free fetal DNA
• test failure
• follow-up
• pregnancy outcome

Article highlights

• There were 274 women (0.23%) who failed to obtain effective NIPT results in this study, including four women for unqualified samples and 270 women for NIPT failure.

• 15 cases showed adverse pregnancy outcomes in case of NIPT failure. Thirteen cases were lost during follow-up, and 67/74 cases showed normal prenatal diagnosis. There were 226 normal newborns and 21 abnormal newborns.

• Logistic regression analysis showed that increased maternal age (OR = 0.988; 95% CI = 0.982-0.994), increased pregnancy age (OR = 0.989; 95%CI = 0.988–0.991), and decreased cell-free fetal DNA concentration (OR = 1.050; 95%CI = 1.043–1.058) were independent risk factors for NIPT failure.

• There was a significant difference in abnormal pregnancy rate between the NIPT success and failure groups (χ2 = 50.943, P < 0.05).

• There was an increased risk of adverse pregnancy outcomes in case of pregnant women who failed to obtain effective NIPT results, in which case, it is necessary to choose amniocentesis or cordocentesis. These diagnostic procedures can test a large number of chromosomal and genetic abnormalities, and can detect birth defects.

• Although NIPT is used universally, the test failure should not be ignored. Understanding the causes of NIPT failure is critical for clinicians to guide patients comprehensively and scientifically.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

One peer reviewer works for a company that commercially offers NIPT. Peer reviewers on this manuscript have no other relevant financial relationships or otherwise to disclose.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This study was supported by a grant from Changsha Maternity and Child Health Hospital (No: 2021YJ21).