Evaluation of sporadic bovine alkaline phosphatase interference in the Beckman Access unconjugated estriol (uE3) assay affecting maternal serum screening results.

OBJECTIVES: Bovine alkaline phosphatase (BALP) mediated interference is a potential issue in the Beckman Access unconjugated estriol (uE3) assay. As the uE3 assay is a component of second trimester maternal serum screening characterizing this interference is essential for delivering accurate trisomy 18 and trisomy 21 risks. DESIGN AND METHODS: Residual serum samples (n = 517) were measured by two different lots of uE3 assay. Scavenger BALP (sBALP) was added to all samples to remove potential BALP dependent interference and assessed using both lots of uE3 reagent. RESULTS: BALP mediated interference was observed in similar frequency in both lots of reagent (~3%), although the patterns of positive and negative interference differed between the lots. Pretreatment with sBALP improved lot-to-lot comparison. The presence of BALP related interference was not related to the concentration of endogenous human alkaline phosphatase. The use of polyethylene glycol and sBALP treatment appeared to mitigate BALP mediated interference equally well, and resulted in concordance in measured uE3 concentrations between reagent lots. Additionally, heterophile antibody interference was observed in two samples affected with BALP interference, and the heterophile antibody interference was resolved by both PEG and heterophile antibody blocking reagent treatment, but not sBALP treatment. While the maternal screen numeric risk for affected samples changed, the risk classification changed from a negative to positive screen in two samples. CONCLUSIONS: Interference in the uE3 assay has the potential to affect maternal serum risk calculations in different reagent lots, and pretreatment of samples with scavenger BALP or PEG should be considered in cases of unexplained uE3 concentrations.

Testing, Monitoring, and Treatment of Thyroid Dysfunction in Pregnancy.

Both hyperthyroidism and hypothyroidism can have adverse effects in pregnancy. The most common causes of thyrotoxicosis in pregnancy are gestational transient thyrotoxicosis and Graves' disease. It is important to distinguish between these entities as treatment options differ. Women of reproductive age who are diagnosed with Graves' disease should be counseled regarding the impact of treatment options on a potential pregnancy. Although the absolute risk is small, antithyroid medications can have teratogenic effects. Propylthiouracil appears to have less severe teratogenicity compared to methimazole and is therefore favored during the first trimester if a medication is needed. Women should be advised to delay pregnancy for at least 6 months following radioactive iodine to minimize potential adverse effects from radiation and ensure normal thyroid hormone levels prior to conception. As thyroid hormone is critical for normal fetal development, hypothyroidism is associated with adverse obstetric and child neurodevelopmental outcomes. Women with overt hypothyroidism should be treated with levothyroxine (LT4) to a thyrotropin (thyroid-stimulating hormone; TSH) goal of <2.5 mIU/L. There is mounting evidence for associations of maternal hypothyroxinemia and subclinical hypothyroidism with pregnancy loss, preterm labor, and lower scores on child cognitive assessment. Although there is minimal risk of LT4 treatment to keep TSH within the pregnancy-specific reference range, treatment of mild maternal thyroid hypofunction remains controversial, given the lack of clinical trials showing improved outcomes with LT4 treatment.

Fetal sex discordance.

Fetal sex discordance is an entity that is becoming more frequent due to the expansion of the cfDNA for prenatal diagnosis. Its incidence can be estimated in 1/1500-2000 pregnancies, a frequency as high as that of some common chromosomopathies. The causes of this phenomenon are multiple and diverse, ranging from laboratory errors to important pathologies such as disorders of sexual differentiation. The management of a case of fetal sex discordance must be structured, starting with the review of the clinical history and the tests performed, and may require the performance of invasive tests to reach a diagnosis. Prevention through adequate pretest counseling and ultrasound confirmation can help to reduce its incidence.

Making the most of the first prenatal visit: The challenge of expanding prenatal genetic testing options and limited clinical encounter time.

OBJECTIVE: Advances in prenatal genetics place additional challenges as patients must receive information about a growing array of screening and testing options. This raises concerns about how to achieve a shared decision-making process that prepares patients to make an informed decision about their choices about prenatal genetic screening and testing options, calling for a reconsideration of how healthcare providers approach the first prenatal visit. METHODS: We conducted interviews with 40 pregnant women to identify components of decision-making regarding prenatal genetic screens and tests at this visit. Analysis was approached using grounded theory. RESULTS: Participants brought distinct notions of risk to the visit, including skewed perceptions of baseline risk for a fetal genetic condition and the implications of screening and testing. Participants were very concerned about financial considerations associated with these options, ranking out-of-pocket costs on par with medical considerations. Participants noted diverging priorities at the first visit from those of their healthcare provider, leading to barriers to shared decision-making regarding screening and testing during this visit. CONCLUSION: Research is needed to determine how to restructure the initiation of prenatal care in a way that best positions patients to make informed decisions about prenatal genetic screens and tests.

Value of increased nuchal translucency in the era of noninvasive prenatal testing with cell-free DNA.

OBJECTIVE: To assess the value of increased nuchal translucency (NT) at first-trimester screening (FTS) despite the superiority of noninvasive prenatal testing with cell-free DNA (cfDNA) for the detection of fetal aneuploidies. METHODS: Retrospective analysis of all FTS data from 2005 to 2015 in our department. Only cases with increased NT and euploid karyotype were considered eligible for inclusion. Abnormal findings, diagnostic work-up, and perinatal outcomes were assessed. RESULTS: Of 18 084 FTS results, 460 (2.5%) showed increased fetal NT, of which 242 (52.6%) underwent invasive karyotyping and 179 (74.0%) had an aneuploidy. Of the remaining 63 cases, 61 (96.8%) showed an additional sonographic finding at FTS and25 (78.1%) had a major anomaly at the second trimester organ scan. The outcome was termination of pregnancy in 28 (44.4%) cases, fetal demise in 5 (7.9%), delivery of an infant with malformation in 21 (33.3%), and delivery of a healthy infant in 7 (11.1%) cases. CONCLUSION: All cases with increased NT would have been detected by cfDNA or by a major sonographic anomaly not later than the second trimester. Routine use of cfDNA, a basic sonogram, and an organ scan could reduce unnecessary work-up and anxiety.

The importance of pre- and post-test counseling for prenatal cell-free DNA screening for common fetal aneuploidies.

INTRODUCTION: Prenatal cell-free DNA screening for common fetal aneuploidies has rapidly changed the paradigm of prenatal care. Despite its advantages compared to conventional screening methods, its unexpectedly rapid implementation in clinical practice has generated several ethical and medical issues and misconceptions. Aggressive commercial marketing of cell-free DNA screening and media dissemination of misleading information have added confusion. Areas covered: This review provides an extensive update and will focus on the importance of pre-and post-test counseling for prenatal cell-free DNA screening not previously discussed extensively in the available literature. Additionally, we report cell-free DNA screening implementation in the largest obstetrical tertiary unit in Finland which is one of few countries that provides all prenatal screening methods free of charge for all women and has a very high uptake of first-trimester screening. This is not a systematical review, but rather a narrative overview which includes the most relevant and recent original publications and reviews covering this issue. Expert opinion: Despite being the most accurate method for screening of common fetal aneuploidies, the knowledge and counseling should be substantially improved. Cell-free DNA screening is not a replacement for diagnostic testing and its use in prenatal testing is complex and limited.

Cell-Free DNA Analysis in Maternal Blood: Differences in Estimates between Laboratories with Different Methodologies Using a Propensity Score Approach.

OBJECTIVES: To evaluate the failure rate and performance of cell-free DNA (cfDNA) testing, mainly in terms of detection rates for trisomy 21, performed by 2 laboratories using different analytical methods. METHODS: cfDNA testing was performed on 2,870 pregnancies with the HarmonyTM Prenatal Test using the targeted digital analysis of selected regions (DANSR) method, and on 2,635 pregnancies with the "Cerba test" using the genome-wide massively parallel sequencing (GW-MPS) method, with available outcomes. Propensity score analysis was used to match patients between the 2 groups. A comparison of the detection rates for trisomy 21 between the 2 laboratories was made. RESULTS: In all, 2,811 patients in the Harmony group and 2,530 patients in the Cerba group had no trisomy 21, 18, or 13. Postmatched comparisons of the patient characteristics indicated a higher no-result rate in the Harmony group (1.30%) than in the Cerba group (0.75%; p = 0.039). All 41 cases of trisomy 21 in the Harmony group and 93 cases in the Cerba group were detected. CONCLUSIONS: Both methods of cfDNA testing showed low no-result rates and a comparable performance in detecting trisomy 21; yet GW-MPS had a slightly lower no-result rate than the DANSR method.

How to correct the impact of ethnicity on effectiveness of the second trimester maternal serum screen of fetal Down syndrome?

Objectives: To compare the performance of second trimester maternal serum screen (MSS) for fetal Down syndrome in Thai population between the conventional method using Caucasian reference ranges with ethnic factor correction (CRR-EC) and the method using specific Thai reference ranges (TRRs). Methods: A prospective database of the MSS project was accessed. The concentrations of alpha fetoprotein (AFP), beta-hCG, and uE3 were converted to their multiple of medians (MoMs) by two methods; CRR-EC for Asian women and TRR. The detection rate and false positive rate derived from the two methods were compared. Results: Of 20,229 cases, 35 women had fetal Down syndrome. The detection rates of both methods were comparable, whereas the false-positive rate of TRR was significantly lower (8.8 versus 11.7%; p < .001). The improvement was mainly caused by more accuracy of the MoMs of beta-hCG, not AFP/uE3, based on TRR. Conclusions: The effectiveness of MSS could be improved by using our own reference ranges instead of using ethnic factor correction. With TRR, the false-positive rate or the number of invasive diagnoses could be significantly decreased without compromise of the detection rate. To improve MSS performance, each population should use its own reference ranges.

Performance and outcomes of noninvasive prenatal testing for twin pregnancies in Japan.

AIM: The purpose of this study was to describe the characteristics of women with twin pregnancies who undergo noninvasive prenatal testing (NIPT) as well as the post-partum and neonatal outcomes of such cases in Japan. METHODS: The study population consisted of women who were pregnant with twins and who underwent NIPT using massively parallel sequencing (MPS) at Nagoya City University Hospital between April 2013 and June 2016. Questionnaires were completed pre-NIPT and post-partum. RESULTS: Among 4009 women who underwent NIPT during the study period, 75 women (1.9%) were pregnant with twins. Fifteen women (20%) experienced vanishing twin/intrauterine fetal deaths at <22 weeks, and 60 women (80%) had normal twin pregnancies at the time of genetic counseling for NIPT. The use of NIPT was correlated with increased proportions of women using assisted reproductive technology (ART). The test had a high performance, with a false-positive rate of 1.7% and no false negatives. CONCLUSION: In this study, NIPT had a high performance, with a false positive rate of 1.7% and no false negatives. When treating women with twin pregnancies, the efficacy of NIPT should be explained during genetic counseling. Further larger studies are required to assess the reliability and validity of NIPT in twin pregnancies.

Factors Associated With Informative Redraw After an Initial No Result in Noninvasive Prenatal Testing.

OBJECTIVE: Noninvasive prenatal testing (NIPT) sometimes fails to provide a test result, usually as a result of low cell-free DNA fetal fraction. We investigated how initial fetal fraction, maternal weight, gestational age, and time between blood sampling contribute to obtaining an informative result when a redraw is performed. METHODS: We performed a retrospective data review of NIPT samples received between January and October 2016 by a commercial laboratory, where the initial blood draw did not yield a result and a second sample was drawn between 5 and 28 days after the initial sampling. We included cases with fetal fraction less than 2.8% (the threshold for "no result" in this laboratory) and those with higher fetal fraction but where the NIPT results could not be interpreted with high confidence. RESULTS: For 4,018 cases in which a redraw was recommended, a result was obtained for the second sample in 2,835 cases (70.6%) (95% CI 69.1-72.0%). For the 2,959 cases with insufficient fetal fraction, there was a result for the second sample in 1,861 cases (62.9%) (95% CI 61.1-64.6%). For this subset, the average increase in fetal fraction was 1.2% with an average interval between draws of 14 days. Informative redraw rate was strongly dependent on maternal weight and fetal fraction measured at the first draw. Gestational age was not an important determinant. Informative redraw rate increased rapidly over the first 8 days after the initial draw and more slowly thereafter. CONCLUSION: Based on fetal fraction in the initial sample, maternal weight, and interval between blood draws, women can be provided with a personalized estimate of their likelihood of a result on redraw. This should aid in the counseling of women faced with the choice of reattempting NIPT, conventional screening, or an invasive diagnostic test.

Next-generation sequencing and the impact on prenatal diagnosis.

INTRODUCTION: The advent of affordable and rapid next-generation sequencing has been transformative for prenatal diagnosis. Sequencing of cell-free DNA in maternal plasma has enabled the development of not only a highly sensitive screening test for fetal aneuploidies, but now definitive noninvasive prenatal diagnosis for monogenic disorders at an early gestation. Sequencing of fetal exomes offers broad diagnostic capability for pregnancies with unexpected fetal anomalies, improving the yield and accuracy of diagnoses and allowing better counseling for parents. The challenge now is to translate these approaches into mainstream use in the clinic. Areas covered: Here, the authors review the current literature to describe the technologies available and how these have evolved. The opportunities and challenges at hand, including considerations for service delivery, counseling, and development of ethical guidelines, are discussed. Expert commentary: As technology continues to advance, future developments may be toward noninvasive fetal whole exome or whole genome sequencing and a universal method for noninvasive prenatal diagnosis without the need to sequence both parents or an affected proband. Expansion of cell-free fetal DNA analysis to include the transcriptome and the methylome is likely to yield clinical benefits for monitoring other pregnancy-related pathologies such as preeclampsia and intrauterine growth restriction.

Characteristics of different risk factors and fasting plasma glucose for identifying GDM when using IADPSG criteria: a cross-sectional study.

BACKGROUND: The Swedish National Board of Health and Welfare (SNBHW) recommended the new diagnostic criteria for GDM based upon Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO) study thresholds. Due to limited knowledge base, no recommendations were made on GDM screening. The aim of this study is to evaluate test characteristics of risk factors and fasting blood glucose as screening tests for diagnosing GDM using diagnostic thresholds based upon HAPO study 1.75/2.0 (model I/II respectively) odds ratio for adverse pregnancy outcomes. METHODS: This cross-sectional, population-based study included all pregnant women who attended maternal health care in Örebro County, Sweden between the years 1994-96. A 75 g OGTT with capillary fasting and 2-h blood glucose was offered to all pregnant women at week 28-32. Risk factors and repeated random glucose samples were collected. Sensitivity, specificity and predictive values of blood glucose were calculated. RESULTS: Prevalence of GDM was 11.7% with model I and 7.2% with the model II criteria. Risk factors showed 28%, (95% CI 24-32) and 31%, (95% CI 25-37) sensitivity for model I and II respectively. A fasting cut off ≥4.8 mmol/l occurred in 24% of women with 91%, (95% CI 88-94) sensitivity and 85%, (95% CI 83-86) specificity using model I while a fasting cut off ≥5.0 mmol/l occurred in 14% with 91%, (95% CI 87-94) sensitivity and 92%, (95% CI 91-93) specificity using model II. CONCLUSION: Risk factor screening for GDM was found to be poorly predictive of GDM but fasting glucose of 4.8-5.0 mmol/l showed good test characteristics irrespective of diagnostic model and results in a low rate of OGTTs.

"Hypothyroidism screening during first trimester of pregnancy".

BACKGROUND: Subclinical hypothyroidism is defined as an elevated thyroid-stimulating hormone level with a normal thyroxin level without signs or symptoms of hypothyroidism. Although it is well accepted that overt hypothyroidism has a deleterious impact on pregnancy, recent studies indicate that subclinical hypothyroidism may affect maternal and fetal health. Studies suggest an association between miscarriage and preterm delivery in euthyroid women positive for anti-peroxidase antibodies and/or anti-thyroglobulin antibodies. A proposal of a new set-point to diagnose SCH was recently published. The aim of this research was to determine the optimal thyroid-stimulating hormone cut-off point to screen for subclinical hypothyroidism in the first trimester of gestation in a population of our clinical area and to determine the diagnostic value of this screening test for detecting anti-thyroid peroxidase antibodies. METHODS: This cross-sectional study determines the cutoff point for SCH screening and evaluates its usefulness to detect TPO Ab using the Receiver Operating Characteristics (ROC) curve. Prevalence of SCH was calculated using as cut-off 2.5 mIU/L, 4 mIU/L, and our TSH 97.5th percentile. The ability to detect positive anti-thyroglobulin antibodies (TG Ab) and anti-thyroid peroxidase antibodies (TPO Ab) in patients with levels of TSH >97.5th percentile was determined by ROC curves. RESULTS: The mean, range and standard deviation of TSH was 2.15 ± 1.34 mIU/L (range 0.03-8.82); FT4 was 1.18 ± 0.13 ng/dL (range 0.94-1.3); TG Ab was 89.87 ± 413.56 IU/mL (range 0.10-4000); and TPO Ab was 21.61 ± 46.27 IU/mL(range 0.10-412.4). The ROC. analysis of the ability of the TSH level to predict the presence of positive TPO Ab found an AUC of 0.563. CONCLUSION: In our population, the TSH cutoff value for gestational SCH screening is 4.7 mIU/L. Using the SEGO recommended 2.5 mIU/L TSH cut-off point, the prevalence of SCH is 37%. Applying the ATA 2017 recommended cutoff point of 4 mIU/L, the prevalence of SCH is 9.6%. Finally, when the cut-off of 4.7 mIU/L (our 97.5th centile) was used, the SCH prevalence is 5%. TSH levels in the first trimester of pregnancy are not useful to detect TPO Ab.

Cell-free fetal DNA testing in prenatal diagnosis: Recommendations of the Polish Gynecological Society and the Polish Human Genetics Society.

This paper contains a joint position of the Polish Gynecological Society and Polish Human Genetics Society on the cell-free fetal DNA testing in prenatal diagnosis. We present situations where the cell-free fetal DNA testing should be applied and cases in which performing of the test is not useful. We indicate what diagnostic steps should be performed before the test and how the test results should be interpreted and followed.

Recommended practice for laboratory reporting of non-invasive prenatal testing of trisomies 13, 18 and 21: a consensus opinion.

OBJECTIVE: Non-invasive prenatal testing (NIPT) for trisomies 13, 18 and 21 is used worldwide. Laboratory reports should provide clear, concise results with test limitations indicated, yet no national or local guidelines are currently available. Here, we aim to present minimum best practice guidelines. METHODS: All laboratories registered in the three European quality assurance schemes for molecular and cytogenetics were invited to complete an online survey focused on services provided for NIPT and non-invasive prenatal diagnosis. Laboratories delivering NIPT for aneuploidy were asked to submit two example reports; one high and one low risk result. Reports were reviewed for content and discussed at a meeting of laboratory providers and clinicians held at the ISPD 2016 conference in Berlin. RESULTS: Of the 122 laboratories that responded, 50 issued reports for NIPT and 43 of these submitted sample reports. Responses and reports were discussed by 72 attendees at the meeting. Consensus opinion was determined in several areas and used to develop best practice guidelines for reporting of NIPT results. CONCLUSIONS: Across Europe, there is considerable variation in reporting NIPT results. Here, we describe minimum best practice guidelines, which will be distributed to European laboratories, and reports audited in subsequent external quality assurance cycles. © 2017 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Impact on spina bifida screening of shifting prenatal Down syndrome maternal serum screening from the second trimester to the first.

OBJECTIVES: Shifting screening for trisomy 21 to the first trimester has resulted in the loss of maternal serum alpha-fetoprotein screening for spina bifida. The aim of this study was to study the impact on open spina bifida prenatal screening. STUDY DESIGN: We reviewed prenatally diagnosed cases of spina bifida over three years: 2009 (only second-trimester screening, MSM2T), 2010 (transient period) and 2011 (majority first-trimester screening, MSM1T). Cases were assigned to three groups based on maternal serum markers (MSM2T, MSM1T and 'not performed'). Gestational age at diagnosis of spina bifida was compared between these three groups and between the years 2009 and 2011. RESULTS: Median gestational ages at diagnosis of the 742 spina bifida cases between the three groups were 22 weeks [18+6 -23], 22+1  weeks [21+3 -23] and 21+4  weeks [14+1 -23], respectively (P < 0.005). The diagnosis was made at 14-20 weeks in 34.7% for MSM2T group versus 8.5% for MSM1T (P < 0.001). Spina bifida diagnosis at 14-20 weeks declined from 38.8% in 2009 to 13.3% in 2011 (P < 0.001). CONCLUSION: Loss of maternal serum alpha-fetoprotein had a tangible effect on the gestational age at diagnosis of spina bifida and resulted in a decrease of 25% of cases of spina bifida detected before 20 weeks. © 2017 John Wiley & Sons, Ltd.