Negative Non-invasive Prenatal Testing Results Research Articles

Outcome of the fetuses with severely increased nuchal translucency thickness in the first trimester.

To study the outcome of pregnancies with severely increased nuchal translucency (NT) thickness at the 11-13-week scan. This study included 162 singleton pregnancies whose fetuses had increased NT thickness ≥ 5.5 mm between September 2013 and August 2018. The cases were divided into two groups: NT ≥ 6.5 mm (n = 112) (group A); and 6.5 mm > NT ≥ 5.5 mm (n = 50) (group B). Fetal (amniotic fluid) or placental (chorionic villous) chromosome analyses were conducted. Subsequent ultrasound findings, pregnancy outcome and structural defects in the neonates were recorded and analyzed. Abnormal karyotype was found in 71% (60/84) (group A) and 57% (21/37) (group B) of the cases respectively. In group A, 15 cases out of 24 with normal karyotype were born. Among these 15 cases, one case died soon after birth and 5 cases had associated abnormalities. In group B, 13 cases out of 18 with normal karyotype or negative noninvasive prenatal testing results and 1 case out of 2 cases with 47,XXY were born. All of them survived with no major anomaly. Incidence of chromosomal aberrations was high in the cases with severely increased NT thickness. But favorable outcome could be expected if the fetus had no chromosomal abnormality and no abnormal findings were found in second trimester ultrasound scan especially in a fetus with increased NT < 6.5 mm.

Psychological and social consequences of non-invasive prenatal testing (NIPT): a scoping review

BackgroundGenomics-based noninvasive prenatal tests (NIPT) allow screening for chromosomal anomalies such as Down syndrome (trisomy 21). The technique uses cell-free fetal DNA (cffDNA) that circulates in the maternal blood and is detectable from 5 weeks of gestation onwards. Parents who choose to undergo this relatively new test (introduced in 2011) might be aware of its positive features (i.e. clinical safety and ease of use); however, they might be less aware of the required decisions and accompanying internal conflicts following a potential positive test result. To show the evidence on psychological and social consequences of the use of NIPT, we conducted a scoping review.MethodsWe systematically searched four electronic databases (MEDLINE (Ovid), Cochrane Library (Wiley), CINAHL (EBSCO) and PsychINFO (EBSCO)) for studies that investigated the psychological or social consequences of the use of NIPT by pregnant women or expecting parents. The search was limited to studies published between 2011 and August 8, 2018. We identified 2488 studies and, after removal of duplicates, screened 2007 titles and abstracts, and then assessed 99 articles in full text (both screenings were done independently in duplicate). We included 7 studies in our analysis.ResultsFive studies assessed anxiety, psychological distress and/or decisional regret among women with validated psychological tests like the Spielberger State Trait-Anxiety Inventory (STAI), the Pregnancy-Related Anxiety Questionnaire-Revised (PRAQ-R), the Kessler Psychological Distress Scale (K6) or the Decisional Regret Scale (DRS). Two studies assessed women’s experiences with and feelings after NIPT in interviews or focus groups. The included studies were heterogeneous in location, study setting, inclusion criteria, outcome assessment, and other characteristics.ConclusionsOnly few studies on psychological consequences of NIPT have been identified. The studies assessed only short-term psychological consequences of NIPT at baseline and/or after receiving the results or after giving birth. Studies show that short term anxiety decreased when women received negative NIPT results and that decisional regret was generally low. We could not identify studies on long term consequences of NIPT, as well as studies on women’s partners’ short and long term outcomes, nor on social consequences of NIPT.

A discordant case in which T21 positive and 47,XXYnegative non-invasive prenatal testing result wasassociated with a 47,XXY mosaic fetus

The authors report a discordant case in which T21 positive and 47,XXY negative non-invasive prenatal testing (NIPT) result was associated with a 47,XXY mosaic fetus confirmed by karyotyping. By investigating the genetic cause, the initial evidence for T21 was demonstrated to be induced by the confined placental mosaicism; the initial lack of evidence for 47,XXY could be attributed to the relatively low effective fetal fraction. This case supported that confined placental mosaicism and low effective fetal fraction are major biological risk factors associated with discordant NIPT results, and provided an unusual case for pre- and post-test NIPT counseling.

Non-invasive prenatal screening for fetal aneuploidy in twin pregnancies by cell-free DNA analysis

Objective: To evaluate the efficacy of Cell-free DNA (cfDNA) based non-invasive prenatal testing (NIPS) in detecting fetal chromosomal aneuploidies among twin pregnancies. Materials and Methods:&nbsp;A cohort of 384 women with twin pregnancies were recruited for chromosomal aneuploidies testing through NIPS. cfDNA was extracted from maternal blood serum and sequenced by massively parallel sequencing (MPS). Result: Two cases of trisomy 21 (T21), one case of trisomy 13 (T13), and two cases of sex chromosomal aneuploidies (SCA) in twin pregnancies were correctly identified through MPS and confirmed their discordant fetal karyotypes (one normal and the other trisomy) by karyotyping; 378 twin pregnancies cases with negative NIPS results were confirmed through postnatal phone follow-up. NIPS detection rate and positive predictive value for T21, T13, and SCA were 100%, respectively, in twin pregnancies; sensitivity and specificity towards T21 and T13 in twin pregnancies were both 100%. Conclusion: cfDNA based NIPS for fetal chromosomal aneuploidy have shown a satisfactory clinical performance in twin pregnancies.

Discordant non-invasive prenatal testing (NIPT) - a systematic review.

With a high sensitivity and specificity, non-invasive prenatal testing (NIPT) is an incomparable screening test for fetal aneuploidy. However, the method is rather newly introduced, and experiences with discordant results are few. We did a systematic review of literature reporting details of false positive and false negative NIPT results. Discordant sex chromosome results were not included. We identified 22 studies reporting case details. In total, 206 discordant cases were included, of which 88% were false positive and 12% false negative. Details on maternal age, gestational age, platform/company, Z-score, fetal fraction, results and explanation were specified. The main reasons for discordant results were confined placental mosaicism, maternal copy number variation, vanished twin, maternal cancer and true fetal mosaicism. A very high percentage of cases (67%) were reported with no obvious biological or technical explanation for the discordant result. The included cases represent only a minor part of the true number of false positive or false negative NIPT cases identified in fetal medicine clinics around the world. To ensure knowledge exchange and transparency of NIPT between laboratories, we suggest a systematic recording of discordant NIPT results, as well as a quality assurance by external quality control and accreditation. © 2017 John Wiley & Sons, Ltd.

NIPT and Informed Consent: an Assessment of Patient Understanding of a Negative NIPT Result.

Since becoming clinically available in 2011, the use of noninvasive prenatal testing (NIPT) to screen for fetal aneuploidy has continued to increase. However, it has been questioned whether the education of patients undergoing NIPT consistently meets informed consent standards. We sought to evaluate patients' basic understanding of NIPT, such as conditions assessed and accuracy. In addition, we investigated patient self-assessment of NIPT knowledge and satisfaction with the testing process. We distributed an anonymous paper survey to pregnant women during prenatal visits following a negative NIPT result. The survey assessed patient NIPT knowledge, gathered pregnancy-specific and demographic information, and allowed respondents to rank their basic understanding of NIPT and provide written feedback about the testing process. A total of 95 completed and 3 partially completed surveys were returned. Participants scored lowest on knowledge questions involving whether a negative NIPT result ensures a healthy baby or eliminates the possibility of Down syndrome. Most perceived themselves to have a good basic understanding of NIPT and two-thirds of the written feedback proposed no changes to NIPT administration. Overall, most patients appear satisfied with their understanding of NIPT and the testing process, yet they may not fully appreciate the limitations of this screening method.

False Negative NIPT Results: Risk Figures for Chromosomes 13, 18 and 21 Based on Chorionic Villi Results in 5967 Cases and Literature Review.

Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the “fetal” DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk. 5967 CV samples of pregnancies at high risk for common aneuplodies were cytogenetically investigated in our centre between January 2000 and December 2011. All cases of fetal trisomy 13, 18 and 21 were retrospectively studied for the presence of a normal karyotype or mosaicism < 30% in short-term cultured (STC-) villi. 404 cases of trisomies 13, 18 and 21 were found amongst 5967 samples (6,8%). Of these 404 cases, 14 (3,7%) had a normal or low mosaic karyotype in STC-villi and therefore would potentially be missed with NIPT. It involved 2% (5/242) of all trisomy 21 cases and 7.3% (9/123) of all trisomy 18 cases. In 1:426 (14/5967) NIPT samples of patients at high risk for common aneuploidies, a trisomy 18 or 21 will potentially be missed due to the biological phenomenon of absence of the chromosome aberration in the cytotrophoblast.

Unexplained False Negative Results in Noninvasive Prenatal Testing: Two Cases Involving Trisomies 13 and 18.

Noninvasive prenatal testing (NIPT) validation studies show high sensitivity and specificity for detection of trisomies 13, 18, and 21. False negative cases have rarely been reported. We describe a false negative case of trisomy 13 and another of trisomy 18 in which NIPT was commercially marketed directly to the clinician. Both cases came to our attention because a fetal anatomy scan at 20 weeks of gestation revealed multiple anomalies. Karyotyping of cultured amniocytes showed nonmosaic trisomies 13 and 18, respectively. Cytogenetic investigation of cytotrophoblast cells from multiple placental biopsies showed a low proportion of nontrisomic cells in each case, but this was considered too small for explaining the false negative NIPT result. The discordant results also could not be explained by early gestational age, elevated maternal weight, a vanishing twin, or suboptimal storage or transport of samples. The root cause of the discrepancies could, therefore, not be identified. The couples involved experienced difficulties in accepting the unexpected and late-adverse outcome of their pregnancy. We recommend that all parties involved in caring for couples who choose NIPT should collaborate to clarify false negative results in order to unravel possible biological causes and to improve the process of patient care from initial counseling to communication of the result.

Impact of noninvasive prenatal testing in regionally dispersed medical centers in the United States

Noninvasive prenatal testing using cell-free DNA is a new alternative to screen for common fetal aneuploidies. It is not known what impact regional location may play on noninvasive prenatal testing implementation and downstream invasive prenatal procedure use in the United States. Six different regionally based centers collected data on noninvasive prenatal testing indication and results between February and November 2012, as well as their invasive prenatal procedure rates before and after offering noninvasive prenatal testing. Statistical analyses were performed using the 2-proportion Z-test. Of 1477 patients who underwent noninvasive prenatal testing; 693 (47%) were from centers in the West; 522 (35.3%) from centers in the East; and 262 (17.7%) from 1 center in the Midwest. Statistically significant differences were observed between West Coast and nonWest Coast sites for gestational age (14.1 weeks; P ≤ .0001). Advanced maternal age (AMA-only) was the most frequent indication in 5 of 6 sites (range, 21.8-62.9%) Atotal of 98 invasive prenatal procedures performed on 94 (6.4%) patients of which 64 (65.3%) were performed at centers in the West. More invasive procedures were performed following negative noninvasive prenatal testing results (n= 61) than abnormal noninvasive prenatal testing results (n= 30). The overall rate of patients undergoing invasive procedure after an abnormal noninvasive prenatal testing result was 32.6% (30 of 92). All 6 centers reported a decrease in invasive procedure volume after noninvasive prenatal testing introduction. This study demonstrates differences in clinical implementation of noninvasive prenatal testing across regionally dispersed centers in the United States, suggesting patient demographics and views toward prenatal testing influence use as well as downstream management.