Multicenter study of first-trimester screening for trisomy 21 in 75 821 pregnancies: results and estimation of the potential impact of individual risk-orientated two-stage first-trimester screening

Screening for pre-eclampsia with competing-risks model using placental growth factor measurement in blood samples collected before 11 weeks' gestation

OBJECTIVES

To describe the distributional properties and assess the performance of placental growth factor (PlGF) measured in blood samples collected before 11 weeks' gestation in the prediction of pre-eclampsia (PE).

METHODS

The study population consisted of pregnant women included in the Pre-eclampsia Screening in Denmark (PRESIDE) study with a PlGF measurement from the routine combined first-trimester screening (cFTS) blood sample collected at 8-14 weeks' gestation. PRESIDE was a prospective multicenter study investigating the predictive performance of the Fetal Medicine Foundation (FMF) first-trimester screening algorithm for PE in a Danish population. In the current study, serum concentration of PlGF in the cFTS blood samples was analyzed in batches between January and June 2021.

RESULTS

A total of 8386 pregnant women were included. The incidence of PE was 0.7% at < 37 weeks' gestation and 3.0% at ≥ 37 weeks. In blood samples collected at 10 weeks' gestation, PlGF multiples of the median (MoM) were significantly lower in pregnancies with preterm PE < 37 weeks compared to unaffected pregnancies. However, PlGF MoM did not differ significantly between pregnancies with PE and unaffected pregnancies in samples collected before 10 weeks' gestation.

CONCLUSIONS

The gestational-age range for PlGF sampling may be expanded from 11-14 to 10-14 weeks when assessing the risk for PE using the FMF first-trimester screening model. There is little evidence to support the use of PlGF in blood samples collected before 10 weeks' gestation. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First-trimester screening for Down syndrome using quadruple maternal biochemical markers

OBJECTIVES

Placental growth factor (PlGF) is used for first-trimester preeclampsia screening and could be combined with other biochemical markers for Down syndrome screening. We aim to estimate the predictive value of the combination of pregnancy-associated plasma protein (PAPP-A), free β-human chorionic gonadotropin (free β-hCG), placental growth factor (PlGF) and α-fetoprotein (AFP) with and without nuchal translucency.

METHODS

Singleton pregnancies recruited at 11-14 weeks and followed until delivery. The four maternal markers were measured using Kryptor (ThermoFisher-BRAHMS) and adjusted for gestational age and maternal characteristics. The risk of Down syndrome was calculated using the Fetal Medicine Foundation algorithm and multivariate linear regression analyses in all cases and in 2,200 controls. Receiver-operator characteristic (ROC) curves were used to calculate the detection and false-positive rates.

RESULTS

Twenty-six (0.2%) cases of Down syndrome were diagnosed among 13,386 participants. The combination of the four biomarkers could have detected 88% (95% CI: 72-97%) of the cases at a false-positive rate of 13% (95% CI: 12-15%). The addition of nuchal translucency would have increased the detection rate to 96% (95% CI: 82-99%) at a false-positive rate of 4% (95% CI: 4-5%) using a 1:300 cut-off and to 100% (95% CI: 89-100%) at a false-positive rate of 6% (95% CI: 5-8%) using a 1:500 cut-off.

CONCLUSIONS

First-trimester screening using biochemical markers allows the identification of approximately 88% of Down syndrome cases for a false-positive rate of 13%. The addition of nuchal translucency raises the detection rate above 95% with a false-positive rate below 5%.

First Trimester Tricuspid Regurgitation: Clinical Significance

Tricuspid regurgitation is a cardiac valvular anomaly that consists of the return of blood to the right atrium during systole due to incomplete valve closure. This structure can be visualized on ultrasound between 11 and 14 weeks of gestation in most cases. Despite being a common finding, even in healthy fetuses, the presence of tricuspid regurgitation may be associated with chromosomal and structural abnormalities. The evaluation of tricuspid flow and the presence of regurgitation on first-trimester ultrasound has shown promising results regarding its role in the early detection of aneuploidies, congenital heart defects, and other adverse perinatal outcomes. This review article aims to demonstrate the importance of tricuspid regurgitation as a secondary marker, and consequently, significant benefits of its early detection when added to the combined first-trimester screening. Its value will be discussed, namely its sensitivity and specificity, alone and together with other current markers in the fetal assessment performed in the first-trimester ultrasound.

Association Between Serum Markers Used in the Routine Prenatal Screening with Pregnancy Outcomes: A Cohort Study

Background

Early detection of adverse pregnancy outcomes is an important topic in prenatal care. This study aimed to evaluate the association between maternal serum markers and pregnancy outcomes.

Materials and Methods

This hospital-based cohort study was performed according to the national Down syndrome screening protocol on 2923 eligible pregnant women. Pregnancies were classified into three groups of based on each biomarker. The participants were followed up until delivery, and the pregnancy outcomes were identified by hospital discharge records.

Results

High levels of free BHCG were significantly associated with an increased risk of preterm birth (B = - 0.31, SE = 0.158, OR = 0.730; P = 0.046). Based on multivariate analysis the high levels of MSAFP had a direct relationship with premature birth (B = - 0.84, SE = 0.361, OR = 0.431, P = 0.020), gestational hypertension (B = - 0.59, SE = 0.354, OR = 0.549. P = 0.091), IUGR (B = - 1.46, SE = 0.433, OR = 0.231, P = 0.001), and fetal death (B = - 1.50, SE = 0.533, OR = 0.223, P = 0.005). Furthermore, an increase in the levels of Inhibin-A could more likely lead to gestational hypertension (B = - 0.63, SE = 0.235, OR = 0.533).

Discussion

According to the result, maternal biomarkers, especially MSAFP, can be beneficial in identifying high-risk cases, in addition to examining the possibility of Down syndrome, facilitating achievement of the desired pregnancy outcomes.

Antenatal care policy in high-income countries with a universal health system: A scoping review

The availability, effectiveness, and access to antenatal care are directly linked with good maternal and neonatal outcomes, making antenatal care an important determinant in health. But to be effective, care must always be appropriate, not excessive, not insufficient. Perinatal outcomes vary within and between countries, raising questions about practices, the use of best evidence in clinical decisions and the existence of clear and updated guidance. Through a scoping review methodology, this study aimed to map the available antenatal care policies for low-risk pregnant women in high-income countries with a universal health system, financed by the government through tax payments. Following searches on the main databases and grey literature, the authors identified and analysed ten antenatal care policies using a previously piloted datachart: Australia, Denmark, Finland, Iceland, Italy, Norway, Portugal, Spain, Sweden and the United Kingdom. Some policies were over 10 years old, some recommendations did not present a rationale or context, others were outdated, or were simply different approaches in the absence of strong evidence. Whilst some recommendations were ubiquitous, others differed either in the recommendation provided, the timing, or the frequency. Similarly, we found wide variation in the methods/strategy used to support the recommendations provided. These results confirm that best evidence is not always assimilated into policies and clinical guidance. Further research crossing these differences with perinatal outcomes and evaluation of cost could be valuable to optimise guidance on antenatal care. Similarly, some aspects of care need further rigorous studies to obtain evidence of higher quality to inform recommendations.

Chromosomal microarray analysis versus noninvasive prenatal testing in fetuses with increased nuchal translucency

OBJECTIVE

To evaluate if the NT value of 2.5 mm ≤ NT < 3.0 mm is an appropriate indication for CMA tests among fetuses with isolated increased NT and NIPT is more suitable instead.

METHODS

A total of 442 fetuses with NT ≥ 2.5 mm were included, in which 241 fetuses underwent karyotype. CMA tests were then carried out when cytogenic analysis showed normal chromosomes and CNV status was compared between 2.5 mm ≤ NT < 3.0 mm and ≥3.0 mm subgroups. For the NIPT evaluation, 201 of 442 fetuses with smaller increased NT (2.5 mm ≤ NT < 3.0 mm) was examined by either NIPT or karyotype.

RESULTS

Of the 241 fetuses with NT ≥ 2.5 mm, 47(19.50%) were identified by karyotype with chromosomal abnormalities. Among 194 cases with normal karyotype, CMA unraveled additional CNVs in 16(8.25%) cases, including 3(1.55%) pathogenic CNVs, 2(1.03%) likely pathogenic CNVs and 11(5.67%) VOUS. After the subgroup analysis, however, only one case (1.16%) of likely pathogenic was identified by CMA among 86 fetuses with NT between 2.5 mm and 3.0 mm, whereas the rest of 15 CNV cases were all presented in fetuses with NT ≥ 3.0 mm. For the NIPT evaluation, the detection rate of 201 fetuses with isolated increased NT between 2.5 and 3.0 mm was 3.98%, which was indifferent to karyotype with the rate of 5%. In comparison with fetuses with 2.5-3.0 mm combined with other risks, the detection rate of karyotype was 26.92%.

CONCLUSION

While no pathogenic CNVs were detected in fetuses, chromosomal aneuploidies and genomic imbalance were found to be the major type of abnormalities when NT was 2.5-3.0 mm. Therefore, our data suggested that CMA should not be recommended when fetuses with an NT value less than 3.0 mm. Instead, NIPT with similar rate of detection as karyotype was recommended for fetuses with isolated increased NT between 2.5 and 3.0 mm.

From screening chromosomal anomalies to early diagnosis of fetal malformations

PURPOSE OF REVIEW

The aim of this review is to understand why and how to improve the detection rate of the fetal anomalies in the first trimester.

RECENT FINDINGS

The role of the first trimester is evolving from aneuploid and basic anatomical screening to a necessary tool to identifying early fetal malformations. In the past 20 years, several studies were conducted to assess the detection rate of anomalies in the first trimester, and despite the improvement in the diagnoses of spina bifida and cleft lip, many anomalies detectable in the first trimester are still being diagnosed in the second trimester scan. Analyzing the factors that improve the detection rate can show the reason why, even in recent years, only 50% of the anomalies are diagnosed in the first trimester.

SUMMARY

Thanks to the improvement in the ultrasound technology, the fetus can be thoroughly studied even in early gestation and it is, therefore, indispensable to increase the detection rate of the anomalies diagnosable from the first trimester. The sonographer's utmost attention should be applied to all pregnancies, not only in high-risk patients, and new protocols based on the mid trimester scan are needed to spread the concept of first trimester anatomical scan.

Benefit versus risk of chromosomal microarray analysis performed in pregnancies with normal and positive prenatal screening results: A retrospective study

Background

Most studies on chromosomal microarray analysis (CMA) and amniocentesis risks have not evaluated pregnancies with low risk for genetic diseases; therefore, the efficacy and safety of CMA and amniocentesis in this population are unclear. This study aimed to examine the benefits and risks of prenatal genetic diagnostic tests in pregnancies having low risk for chromosomal diseases.

Methods and findings

In this retrospective study, we used clinical data from a large database of 30,830 singleton pregnancies at gestational age 16–23 weeks who underwent amniocentesis for karyotyping with or without CMA. We collected socio-demographic, medical and obstetric information, along with prenatal screening, CMA and karyotyping results. Fetal loss events were also analysed. CMA was performed in 5,837 pregnancies with normal karyotype (CMA cohort). In this cohort, 4,174 women had normal prenatal screening results and the risk for identifying genetic abnormalities with >10% risk for intellectual disability by CMA was 1:102, with no significant difference between maternal age groups. The overall post-amniocentesis fetal loss rate was 1:1,401 for the entire cohort (n = 30,830) and 1:1,945 for the CMA cohort (n = 5,837). The main limitation of this study is the relatively short follow-up of 3 weeks, which may not have been sufficient for detecting all fetal loss events.

Conclusion

The low risk for post-amniocentesis fetal loss, compared to the rate of severe genetic abnormalities detected by CMA, suggests that even pregnant women with normal prenatal screening results should consider amniocentesis with CMA.

First-trimester presentation of ultrasound findings in trisomy 13 and validation of multiparameter ultrasound-based risk calculation models to detect trisomy 13 in the late first trimester

OBJECTIVES

To identify the most common ultrasound patterns of markers and anomalies associated with Patau syndrome (PS), to explore the efficacy of multiparameter sonographic protocols in detecting trisomy 13 (T13) and to analyze the influence of maternal age (MA) on screening performance.

METHODS

The project was a prospective study based on singleton pregnancies referred for a first-trimester screening examination. The scan protocol included nuchal translucency (NT), fetal heart rate (FHR), secondary ultrasound markers [nasal bone (NB), tricuspid regurgitation (TR), ductus venosus reversed a-wave (revDV)] and major anomaly findings.

RESULTS

The study population comprised 6133 pregnancies: 6077 cases of euploidy and 56 cases of T13. Statistically significant differences were found in MA, FHR, NT, absence of NB, presence of revDV, TR and single umbilical artery. Fourteen cases of T13 (25%) demonstrated no markers of aneuploidy. The best general detection rate (DR) (DR of 78.6% with an false positive rate (FPR) of 1.2%) was obtained for a cutoff of 1/300 utilizing the "NT+T13" algorithm. The logistic regression model revealed that the central nervous system (CNS) anomalies had the greatest odds ratio (of 205.4) for T13.

CONCLUSIONS

The effectiveness of the multiparameter sonographic protocol used for T13 screening showed promising results in patients older than 36 years and suboptimal results in patients between 26 and 36 years old. When screening for T13 left heart defects, CNS anomalies, abdominal anomalies, FHR above the 95th percentile, increased NT, revDV and lack of NB should receive specific attention.

Women's experiences of counselling in cases of a screen-positive prenatal screening result

OBJECTIVE

To study women's apprehensions, understanding and experiences of counselling concerning a screen-positive result in screening for fetal chromosomal defects.

METHODS

A questionnaire study including different steps of the prenatal screening process was carried out in Helsinki University Hospital. Women's experiences concerning counselling immediately after a screen-positive result and during further examinations in the Fetal Medicine Unit (FMU) were analyzed.

RESULTS

143 women filled in the questionnaire. Less than half of the women considered the primary counselling after a screen-positive result to be explicit (43.9%) and sufficient (43.1%). In the FMU, 88.3% and 89.8% of women were satisfied with the explicitness and sufficiency of counselling. Most women (75%) experienced worry before further examinations but less than half (45%) had considered their personal values concerning diagnostic tests. Half (50.5%) of women expected the worry to continue even if diagnostic tests turn out normal. Most (81%) women were aware that diagnostic tests are voluntary and were confident (85.3%) with their decision to participate.

CONCLUSIONS

After a screen-positive result, women have unanswered questions, experience anxiety and confusion. The possibility of an abnormal screening result is not seriously considered beforehand. To enable an informed consent for prenatal screening, improvements in prescreening counselling during the first visits of antenatal care need to be made.

First trimester combined screening test for aneuploidies in anti-Ro carriers pregnant women

INTRODUCTION

Anti-Ro/SSA and anti-La/SSB antibodies are associated with neonatal lupus and congenital heart block. Controversial results regarding perinatal outcomes are found and less is known about aneuploidy screening. The hypothesis is that the presence of anti-Ro and/or anti-La antibodies influences the levels of PAPP-A and ß-HCG, thus interfering in the calculation of risk of aneuploidies.

MATERIAL AND METHODS

Fifty-five anti-Ro/SSA positive pregnant women were included. The demographic characteristics and laboratory variables were studied. Data concerning chromosomopaties screening were also recorded.

RESULTS

PAPP-A and β-HCG levels were calculated (as well as NT and CRL) and compared with a healthy cohort of 12971 pregnant women. PAPP-A levels in mg/mL were lower significatively. In anti-La/SS-B cohort, significant differences were found in PAPP-A in mg/mL and in MoM. Combined risks for Down syndrome (DS) in both groups were higher but the differences were due to age.

CONCLUSIONS

Serum levels of PAPP-A were significative lower but not confirmed when adjusted to MoM. This will have to be confirmed in studies with a larger number of patients and to check whether there is an impact in the calculation of DS risk or not. They could represent a group of pregnant women with significantly a higher risk of adverse perinatal outcome. Key Points • Pregnant patients with anti-Ro/SS-A ant/or anti-La/SS-B antibodies have low PAPP-A levels compared with pregnant women without antibodies. • PAPP-A levels are used in obstetrics for aneuploidies screening in the first trimester, so in these patients, there could be more false positive screening. • In these findings are verified in trials with a larger number of patients, a correction variable would have to be applied for the aneuploidies screening calculation. • Also, low PAPP-A levels are correlated with poor placentation, that is to say, more risk of miscarriages, small fetus for gestational age, and preeclampsia. This is another topic to take into consideration in this population.

First-trimester prediction of small-for-gestational age in pregnancies at false-positive high or intermediate risk for fetal aneuploidy

OBJECTIVES

To explore the risk of small-for-gestational age (SGA) and fetal growth restriction (FGR) and to test the performance of first-trimester screening for SGA and FGR in women with a false-positive high or intermediate risk for aneuploidy.

METHODS

This was a prospective cohort study of women with a singleton pregnancy attending for a routine first-trimester scan. The risks of aneuploidy and preterm SGA (defined as birth weight < 10^th percentile with delivery before 37 weeks) were determined according to Fetal Medicine Foundation algorithms. In non-malformed euploid pregnancies, the predictive performance of both the aneuploidy and preterm SGA risks was evaluated for SGA, FGR (defined as birth weight < 3^rd centile), preterm SGA and early SGA (delivery before 34 weeks), using receiver-operating-characteristics (ROC) curve analysis, in those with a high or intermediate risk of aneuploidy and in the overall population.

RESULTS

A total of 2053 pregnancies were included in the analysis, of which 191 (9.3%) were at high or intermediate risk for aneuploidy (≥ 1/1000) and 304 (14.8%) were at high risk for preterm SGA (≥ 1/100). In total, there were 140 (6.8%) cases of SGA, 61 (3.0%) of FGR, 44 (2.1%) of preterm SGA and 33 (1.6%) of early SGA. Among women with a false-positive high or intermediate risk for aneuploidy, the rates of SGA, FGR, preterm SGA and early SGA were 13.6% (26/191), 7.9 % (15/191), 6.8% (13/191) and 5.8% (11/191), respectively. Compared with women with a first-trimester low risk for preterm SGA, regardless of aneuploidy risk, those with a high risk for preterm SGA and a high or intermediate risk for aneuploidy had relative risks for SGA, FGR, preterm SGA and early SGA of 6 (95% CI, 3.9-9), 9.2 (95% CI, 5.1-16.5), 13.4 (95% CI, 6.9-26.1) and 17.6 (95% CI, 8.1-38.2), respectively. The predictive performance for SGA of the preterm SGA algorithm was higher in women at high or intermediate risk for aneuploidy than in the overall population (area under the ROC curve (AUC), 0.8 vs 0.7; P < 0.001). Among women at high or intermediate risk for aneuploidy, the predictive performance of the preterm SGA algorithm was better than that of the aneuploidy algorithm for SGA (AUC, 0.80 vs 0.58; P = 0.003), preterm SGA (AUC, 0.85 vs 0.65; P = 0.013) and early SGA (AUC, 0.86 vs 0.60; P = 0.002).

CONCLUSION

In women with a first-trimester false-positive high or intermediate risk of aneuploidy, further screening for SGA allows stratification of the risk for fetal growth disorders. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Diagnosis of major heart defects by routine first-trimester ultrasound examination: association with increased nuchal translucency, tricuspid regurgitation and abnormal flow in ductus venosus

OBJECTIVE

To examine the association between fetal major heart defects and increased nuchal translucency thickness (NT), tricuspid regurgitation and abnormal flow in the ductus venosus in a large population of singleton pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation.

METHODS

This was a retrospective study of prospectively collected data from singleton pregnancies attending for a routine ultrasound scan at 11-13 weeks' gestation, which included examination of fetal anatomy, measurement of NT and assessment of blood flow across the tricuspid valve and in the ductus venosus, according to a standardized protocol. The incidence of fetal NT ≥ 95^th and ≥ 99^th percentiles, tricuspid regurgitation and reversed a-wave in the ductus venosus in fetuses with and those without a major heart defect was determined and the performance of each marker and their combination in the detection of major heart defects was calculated.

RESULTS

The study population of 93 209 pregnancies with no apparent chromosomal abnormality included 211 (0.23%) with a fetal major heart defect and 92 998 morphologically normal neonates. In 113 (53.6%) cases with a major heart defect, the diagnosis was made at the 11-13-week scan, in 82 (38.9%) at the 18-24-week scan, in 10 (4.7%) at the third-trimester scan and in six (2.8%) postnatally. At the 11-13-week scan, we diagnosed all cases of tricuspid or pulmonary atresia and polyvalvular dysplasia, > 90% of cases of hypoplastic left heart syndrome or atrioventricular septal defect, about 60% of complex heart defects and cases of left atrial isomerism (interrupted inferior vena cava with normal intracardiac anatomy), 30-40% of cases of tetralogy of Fallot and arch abnormalities, 25% of tricuspid valve abnormalities and about 15% of cases of transposition of the great arteries, but none of aortic or pulmonary stenosis or common arterial trunk. Fetal NT ≥ 95^th or ≥ 99^th percentile, tricuspid regurgitation or abnormal ductus venosus flow was observed in 77 (36.5%), 45 (21.3%), 61 (28.9%) and 58 (27.5%) fetuses with a major heart defect, respectively, and in 5678 (6.1%), 857 (0.9%), 1136 (1.2%) and 1644 (1.8%) of those without a heart defect. Any one of NT ≥ 95^th percentile, tricuspid regurgitation or abnormal flow in the ductus venosus was found in 117 (55.5%; 95% CI, 48.5-62.3%) fetuses with a heart defect and in 8166 (8.8%; 95% CI, 8.6-9.0%) of those without a heart defect. Any one of NT ≥ 99^th percentile or the other two markers was found in 99 (46.9%; 95% CI, 40.0-53.9%) fetuses with a heart defect and in 3517 (3.8%; 95% CI, 3.7-3.9%) of those without a heart defect.

CONCLUSION

At 11-13 weeks' gestation, measurement of fetal NT and assessment of flow across the tricuspid valve and in the ductus venosus can lead to early diagnosis of major heart defect. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The evaluating of pregnancy-associated plasma protein-A with the likelihood of small for gestational age

Objective

Recently, strong evidences were obtained on the association between low pregnancy-associated plasma protein-A (PAPP-A) levels in the first trimester and poor outcomes of pregnancy.

Methods

This cross-sectional study was conducted on all pregnant women who were referred to the Obstetrics and Gynecology Clinic at Imam Hossein Hospital in Tehran, Iran in 2014. Women were asked to attend clinical examinations and screening at 11–14 weeks of gestation.

Results

Based on the definition, 14.5% of neonates found to be small for gestational age (SGA). There was a strong association between PAPP-A levels and birth weight. The mean PAPP-A level in the mothers of neonates who were SGA was significantly lower than those without this poor outcome. Based on the receiver operating characteristic curve analysis, serum PAPP-A level was a main determinant in the prediction of SGA neonates.

Conclusion

The serum PAPP-A level at 11–13 weeks of gestation can effectively predict the increased risk for fetal growth retardation. In patients in this study, the best cutoff value for PAPP-A was 0.75 MOM, which signifies that lower levels of this marker can predict fetal growth restriction with high sensitivity and specificity.

Fetal tricuspid regurgitation in second trimester of pregnancies at risk for fetal chromosomal defects

PURPOSE

To determine the prevalence and screening performance for detection of Down syndrome of fetal tricuspid regurgitation in the second trimester of pregnancies at risk for fetal chromosomal defects.

METHODS

A prospective study was carried out on pregnant women at risk for fetal chromosomal defects who had amniocentesis or cordocentesis for fetal karyotyping at 16 to 23 weeks' gestation, between February 2017 and January 2018. An assessment of the fetal tricuspid valve was conducted before any invasive procedure. Tricuspid regurgitation was defined as flow reversal for at least half of systole, with a maximum velocity of ≥100 cm/s.

RESULTS

In the 486 cases studies, fetal tricuspid regurgitation was found in 21 (4.3%), and 10 fetuses had Down syndrome. The tricuspid regurgitation was found in 15 (3.2%) of the 462 euploid fetuses, in 5 (50%) of the Down syndrome fetuses, and in 1 (7.1%) of the fetuses with other chromosome abnormalities. Tricuspid regurgitation was found as an isolated marker in 2 of the 10 Down syndrome fetuses. The sensitivity, specificity, positive predictive value, and negative predictive value to screen for Down syndrome were 50%, 96.8%, 25%, and 98.9%, respectively.

CONCLUSIONS

Tricuspid regurgitation showed a high prevalence in fetal Down syndrome at the gestational age of 16 to 23 weeks and was an isolated marker in 20% of them.

Association of Low Maternal Pregnancy-associated Plasma Protein A with Adverse Perinatal Outcome

The aim is to provide an overall view of the association of low pregnancy-associated plasma protein A (PAPP-A) levels with adverse perinatal outcomes. The available literature in PubMed/Medline regarding PAPP-A and adverse pregnancy outcomes was searched for related articles, including terms such as “PAPP-A,” “intrauterine growth restriction (IUGR),” “small for gestational age (SGA),” “stillbirth,” “adverse outcome,” and others. The fifth percentile is supported by many recent studies to be PAPP-A’s cutoff for adverse outcome detection and the increased risk seems to be extremely high below 0.2 PAPP-A MoM (multiple of the median). Apart from chromosomal abnormalities, preeclampsia, intrauterine fetal demise, and pregnancy loss have been associated with maternal serum PAPP-A. For results below the first centile, PAPP-A has a strong positive predictive value for SGA and IUGR. Except for its vital role on the cleavage of insulin-like growth factor binding proteins (IGFBP), PAPP-A has proven to be a reliable marker for prenatal screening. Even though PAPP-A as a single predictor proved to be valuable for the prediction of some adverse perinatal outcomes, in some cases, a combination of PAPP-A to other maternal serum markers led to an increase in detection rates. PAPP-A is a promising maternal serum marker for pregnancy outcome prediction with more studies needed in order for its potentials to be fully understood and exploited.

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.

Two-stage screening for preterm preeclampsia at 11-13 weeks' gestation

BACKGROUND

Screening for preeclampsia at 11-13 weeks' gestation by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index, and serum placental growth factor (triple test) can predict about 90% of preeclampsia, with delivery at <32 weeks (early-preeclampsia), and 75% of preeclampsia with delivery at <37 weeks (preterm preeclampsia), at a screen-positive rate of 10%. In pregnancies identified as being at high risk for preeclampsia by such screening, administration of aspirin (150 mg/d from 11 to 14 weeks' gestation to 36 weeks) reduces the rate of early preeclampsia by about 90% and preterm preeclampsia by about 60%. Recording of maternal history and blood pressure are part of routine prenatal care, but measurement of uterine artery pulsatility index and placental growth factor require additional costs.

OBJECTIVE

To explore the possibility of carrying out first-stage screening in the whole population by maternal factors alone or a combination of maternal factors, mean arterial pressure and uterine artery pulsatility index or maternal factors, mean arterial pressure, and placental growth factor and proceeding to second-stage screening by the triple test only for a subgroup of the population selected on the basis of the risk derived from first-stage screening.

STUDY DESIGN

The data for this study were derived from prospective nonintervention screening for preeclampsia at 11⁺⁰ to 13⁺⁶ weeks' gestation in 61,174 singleton pregnancies. Patient-specific risks of delivery with preeclampsia at <37 and <32 weeks' gestation were calculated using the competing risks model to combine the prior distribution of the gestational age at delivery with preeclampsia, obtained from maternal characteristics and medical history, with various combinations of multiple of the median values of mean arterial pressure, uterine artery pulsatility index, and placental growth factor. We estimated the detection rate of preterm-preeclampsia and early-preeclampsia at overall screen-positive rate of 10%, 15%, and 20% from a policy in which first-stage screening of the whole population is carried out by some of the components of the triple test and second-stage screening by the full triple test on women selected on the basis of results from first-stage screening.

RESULTS

If the method of first-stage screening is maternal factors, then measurements of mean arterial pressure, uterine artery pulsatility index, and placental growth factor can be reserved for only 70% of the population, achieving similar detection rate and screen-positive rate as with screening the whole population with the triple test. In the case of first-stage screening by maternal factors, mean arterial pressure, and uterine artery pulsatility index, then measurement of placental growth factor can be reserved for only 30-40% of the population, and if first-stage screening is by maternal factors, mean arterial pressure, and placental growth factor, measurement of uterine artery pulsatility index can be reserved for only 20-30% of the population. Empirical results were consistent with model-based performance.

CONCLUSION

Two-stage screening and biomarker testing for only part of the population will have financial benefits over conducting the test for the entire population.

Reference centile charts of first-trimester aneuploidy screening & Doppler parameters for Indian population

Background & objectives:

The risk estimation for foetal aneuploidies in the first trimester of pregnancy uses reference curves based on western data. The objective of this study was to construct the reference curves of first-trimester foetal aneuploidy screening parameters for the Indian women.

Methods:

Cross-sectional data were obtained from 1204 singleton pregnancies between the crown-rump length (CRL) of 40-84 mm. Linear regression models were constructed; the mean, median and standard deviation were derived as a function of CRL.

Results:

The mean value of CRL was 61.3 mm. The regression analysis showed a significant correlation between all variables and CRL (P<0.001). There was a positive correlation of CRL with nuchal translucency (NT) (y=0.010x+0.629, R²=0.116) and pregnancy-associated plasma protein-A (PAPP-A) (y=0.107x−1.079, R²=0.173), whereas inverse correlation was seen with free β-human chorionic gonadotropin (β-hCG) (y=−0.409x+75.025, R²=0.018) and Doppler parameters pulsatility index (PI) (y=−0.008x+1.924 R²=0.053). The centile charts of NT, PAPP-A, free β-hCG and uterine artery (Ut A) Doppler PI were constructed.

Interpretation & conclusions:

The reference centile charts of first trimester aneuploidy screening along with Doppler parameters were derived in Indian pregnant women. These centile charts may be used as a reference for clinical use in Indian population.

National screening guidelines and developments in prenatal diagnoses and live births of Down syndrome in 1973-2016 in Denmark

INTRODUCTION

Denmark was the first country in the world to implement a national, free-for-all offer of prenatal screening for Down syndrome to all pregnant women. It has a high uptake (>90%) compared to other countries. Thus, Denmark offers an interesting case for investigating the consequences of implementing comprehensive, national prenatal screening guidelines. The aim of this study was to describe the historical developments in invasive procedures, pre-/postnatal diagnoses of Down syndrome and Down syndrome live births in the period 1973-2016 in Denmark.

MATERIAL AND METHODS

Data on invasive procedures, pre- and postnatal Down syndrome diagnoses were retrieved from the Danish Cytogenetic Central Registry.

RESULTS

From 1973 to 1993, screening based on maternal age and high-risk indications resulted in a constant increase in invasive procedures. After the introduction of the triple test in 1994, invasive procedures decreased for the first time in 20 years. Following the introduction of an offer of combined screening to all pregnant women in 2004, the number of invasive procedures decreased markedly, while there was a concurrent increase in prenatal diagnoses of Down syndrome. Additionally, the number of Down syndrome live births decreased suddenly and significantly, but subsequently stabilized at 23-35 annual live births. Of these, the majority were diagnosed postnatally.

CONCLUSION

Though prenatal screening technologies constantly improve, it was the introduction of and adherence to national guidelines that resulted in marked shifts in screening procedures and outcome in Denmark.

Reference values of nuchal fold thickness in an Iranian population sample

Background:

Considering that ethnicity and gestational age (GA) could affect the value of nuchal fold thickness (NFT) in mid-trimester, we aimed to determine the reference intervals of NFT values for each gestational week from 16 to 24 weeks of pregnancy among a group of Iranian pregnant women.

Materials and Methods:

In this cross-sectional study, medical files of pregnant women who underwent fetal anomaly scanning at 16–24 weeks of gestation were reviewed and the following data were extracted: GA, value of NFT, value of nuchal translucency (NT) in their previous ultrasound study, if available, and head circumference (HC). The 5^th, 25^th, 50^th, 75^th, and 95^th percentiles of NFT for each gestational week were determined. The association between NFT and HC, GA, and NT were also determined.

Results:

Medical files of 882 pregnant women were studied. The expected 95^th percentile value of NFT between 16^th and 24^th weeks of gestation ranged from 4 mm to 5.9 mm. The mean (standard deviation) of NFT increased with GA from 2.67 (0.90) mm at 16^th weeks to 4.69 (0.71) mm at 24^th weeks. There was a significant positive association between NFT and GA (β = 1.11, p < 0.001), HC (β = 0.21, p < 0.001), and NT (β = 0.351, p < 0.001).

Conclusion:

The findings of this study revealed that before the 20^th week of gestation, the appropriate cutoff value of NFT is 5 mm, and for 21^st to 24^th weeks, the proper cutoff is 6 mm. However, for providing more conclusive results, further studies with larger sample size and considering the impact of other influencing variables are recommended.

Reference values of the ductus venosus pulsatility index for pregnant women between 11 and 13+6 weeks of gestation

Purpose: The ductus venosus pulsatility index velocity (DV PIV) has become a popular ultrasonographic measurement during the first trimester of pregnancy. The value of the DV PIV has been the topic of ongoing discussion in the literature, and its reference value in the normal population has not yet been established. Therefore, we aimed to determine a reference value for the DV PIV.Materials and Methods: We retrospectively evaluated our records of first-trimester ultrasonography performed between 2016 and 2017. Our inclusion criteria were as follows: singleton pregnancy; crown-rump length (CRL) between 45 and 84 mm; absence of structural abnormalities on the ultrasound examination; and absence of chromosomal abnormalities. Records of 820 patients were evaluated. According to the inclusion criteria, records of 458 patients were included in this study. All ultrasound examinations were performed by a single operator with the Voluson E8 (5- to 8-MHz 3 D transducer; General Electric Healthcare, Little Chalfont, UK) via the transabdominal route. Gestational weeks were designated according to CRL measurements at the beginning of the examination. Nuchal translucency (NT), nasal bone visualization (NB), tricuspid valve regurgitation (TR), "a"-wave pattern, DV PIV, S-wave (peak systolic velocity), D-wave (peak diastolic velocity), a-wave (atrial contraction in late diastole), and time-averaged maximum velocity (TAMXV) measurements were performed. To evaluate the DV Doppler images, a mid-sagittal view of the fetal profile was obtained. Color Doppler and pulse Doppler gate were used in the distal portion of the umbilical sinus, and at least three typical DV waveforms were detected. The SPSS 21.0 statistical program (IBM, Armonk, NY) was used to analyze variables.Results: The mean age, body mass index, CRL, gestational age, and NT values were 30.3 years (range, 18-45), 23.9 kg/m² (range, 15.5-46.6), 59.5 mm (range, 45-79), 12.3 weeks (range, 11.2-13.6), and 1.58 mm (range, 0.73-2.62), respectively. The median gravidity and parity were 2 (1-8) and 0 (0-4), respectively. The "a"-wave pattern was identified in all cases, but TR was not detected in any of the cases. Measurements of DV PIV with a Gaussian distribution were suitable according to the Shapiro-Wilk test (p = .252). The mean DV PIV was 0.98, and the fifth and 95th percentiles were 0.73 and 1.22 (±2 SD), respectively. A statistical analysis of our cohort revealed that DV PIV values less than 0.73 and more than 1.22 were beyond the normal range. The mean S-wave, D-wave, a-wave, and TAMXV values were 31.18, 25.64, 8.68, and 22.72 cm/s, respectively.Conclusions: The value of DV PIV measurements is debated in the literature. Using our cohort, we defined the means and ranges of DV PIV. Determining the normal ranges of DV PIV could be helpful to anticipate congenital or chromosomal abnormalities. Further studies are needed to demonstrate the clinical importance of DV PIV, especially for patients with abnormal DV PIV measurements.

First-trimester risk assessment based on ultrasound and cell-free DNA vs combined screening: a randomized controlled trial

OBJECTIVE

This was a randomized controlled trial to compare risk assessment by first-trimester combined screening (FTCS) with an approach that combines a detailed ultrasound examination at 11-13 weeks' gestation and cell-free DNA (cfDNA) analysis.

METHODS

Pregnant women with a normal first-trimester ultrasound examination at 11-13 weeks' gestation (fetal nuchal translucency (NT) ≤ 3.5 mm and no fetal defects) were randomized into one of two groups. In the first group, risk of aneuploidy was assessed using FTCS based on the most recent UK Fetal Medicine Foundation algorithm. In the second group, risk assessment was based on ultrasound findings and cfDNA analysis. An additional tube of blood was collected for FTCS in case the cfDNA analysis was uninformative. Primary outcome was false-positive rate in screening for trisomy 21. A case was considered false positive if the karyotype was not trisomy 21 and if the risk for trisomy 21 was >1:100, irrespective of the method of risk calculation. Results were compared using 95% CIs using the Clopper-Pearson method.

RESULTS

Between October 2015 and December 2016, 1518 women with singleton pregnancy underwent first-trimester screening. Thirty-one (2.0%) pregnancies were not eligible for randomization due to increased NT (> 3.5 mm) and/or fetal defect. After exclusion of women who declined randomization (n = 87) and cases of fetal death and loss to follow-up (n = 24), 688 pregnancies were randomized into the FTCS arm and 688 into the ultrasound + cfDNA analysis arm. There were no differences in maternal and gestational age, maternal weight and BMI, ethnicity, use of assisted reproduction and cigarette smoking between the two arms. In the ultrasound + cfDNA analysis arm, median risk for trisomy 21 was 1 in 10 000. None of the cases had a risk above 1: 100 (95% CI, 0.0-0.5%). In the FTCS arm, the median risk for trisomy 21 was 1 in 3787 and in 17 cases, the risk was higher than 1:100, which corresponds to 2.5% (95% CI, 1.5-3.9%) of the FTCS study-arm population.

CONCLUSION

Our study has shown that first-trimester risk assessment for trisomy 21 that includes a detailed ultrasound examination as well as NT measurement and is followed by cfDNA testing is associated with a significant reduction in the false-positive rate compared with FTCS. This approach obviates the need for maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A in screening for fetal aneuploidy. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound screening for complications in twin pregnancy

In the decades since the introduction of ultrasound into routine obstetric practice, the advantages of ultrasound have moved beyond the simple ability to identify multiple pregnancies antenatally to the possibility of screening them for fetal anomalies, pre-eclampsia, preterm birth, and the complications specific to monochorionic pregnancies. Screening studies have often excluded twins because physiological differences impact on the validity and sensitivity of the screening tests in routine use in singletons, and therefore, the evidence of screening performance in multiple pregnancy lags behind the evidence from singleton pregnancies. In general, most pregnancy complications are more common in twin pregnancy, but screening tests are less accurate or well validated. In this review article we present the current state of the evidence and avenues for future research relating to the use of ultrasound and screening for complications in twin pregnancies, including the monochorionicity-related pathologies, such as twin-twin transfusion syndrome, selective growth restriction, twin anaemia-polycythaemia sequence and twin reversed arterial perfusion sequence.

Utilizing two-tiered screening for early detection of autism spectrum disorder

Despite advances in autism screening practices, challenges persist, including barriers to implementing universal screening in primary care and difficulty accessing services. The high false positive rate of Level 1 screening methods presents especially daunting difficulties because it increases the need for comprehensive autism evaluations. This study explored whether two-tiered screening-combining Level 1 (Modified Checklist for Autism in Toddlers, Revised with Follow-Up) and Level 2 (Screening Tool for Autism in Toddlers and Young Children) measures-improves the early detection of autism. This study examined a sample of 109 toddlers who screened positive on Level 1 screening and completed a Level 2 screening measure prior to a diagnostic evaluation. Results indicated that two-tiered screening reduced the false positive rate using published Screening Tool for Autism in Toddlers and Young Children cutoffs compared to Level 1 screening alone, although at a cost to sensitivity. However, alternative Screening Tool for Autism in Toddlers and Young Children scoring in the two-tiered screening improved both positive predictive value and sensitivity. Exploratory analyses were conducted, including comparison of autism symptoms and clinical profiles across screening subsamples. Recommendations regarding clinical implications of two-tiered screening and future areas of research are presented.

The first trimester combined test for aneuploidies - a single center experience

PURPOSE

We present the results of the systematic application of the first trimester combined test for aneuploidies, in a Romanian center.

METHODS

Since October 2009, in Filantropia Hospital in Bucharest, we have systematically been using the FMF (Fetal Medicine Foundation) combined first trimester test to screen for common aneuploidies at 11 to 13 + 6 weeks of gestation. We assessed the crown to rump length (CRL), nuchal translucency, fetal heart rate as well as PAPP-A, and free β-hCG in maternal serum. We evaluated additional first trimester ultrasound markers in most of the cases. The individual risk for aneuploidies was calculated using the FMF algorithm.

RESULTS

Pregnancy outcome is known for 6030 euploid fetuses and 42 aneuploid fetuses from our screening population. The detection rate for trisomy 21 of the combined test was 87.5% for a screen positive rate of 1.96%. All of the trisomy 18 and trisomy 13 cases were detected prenatally. Some of the trisomy 18 cases proved not to be symptomatic in the first trimester.

CONCLUSIONS

Our results are similar to those of the main studies on the FMF method of first trimester screening for aneuploidies. Our numbers are small because of limited availability of the very specialized resources involved.

Detection of trisomies 13, 18 and 21 using non-invasive prenatal testing

The clinical performance of non-invasive prenatal testing (NIPT) in the Down's syndrome screening based on 1,901 pregnant women in a Chinese hospital was investigated. This was a retrospective analysis of NIPT study in singleton pregnancy (n=1,901). The NIPT test is offered routinely as a prenatal screening test for common fetal aneuploidies, including trisomy 13 (T13), T18 and T21 to pregnant women with risk factors of one or more anomalies. Maternal peripheral blood (5 ml) was collected in an ethylenediaminetetraacetic acid (EDTA) tube at a gestational age of 12+0 to 32+6 weeks. The samples were delivered at -80°C to the certified Shenzhen BGI Clinical Laboratory Center. Sequencing data were analyzed using a proprietary algorithm. Women with positive NIPT results were recommended to receive karyotype analysis and amniotic fluid puncture for further validation. The cases were followed up for 56 days after delivery. All the patients underwent ultrasound examination, and the majority of patients (91.16%) showed normal findings. In contrast, 136 (7.15%) showed ultrasound anomalies. The most common anomaly was echogenic heart focus (n=80), accounting for 4.21% of the patients. Twenty-two cases were classified by the NIPT to be positive for the T21 (n=15), T18 (n=5) and T13 (n=2), respectively, while the others (n=1,879) were classified to be NIPT negative cases. Among these cases, the fetal outcome data were obtained in 1,483 cases, while 396 were lost to follow-up. The majority of cases (75.47%) were normal at birth. Neonatal death was observed in 1 case. Five pregnant women decided termination of pregnancy despite the presence of NIPT negativity. In conclusion, NIPT technique is feasible for the prenatal screening of T18 and T21 with higher sensitivity and specificity compared with conventional methods.

First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.

SEARCH METHODS

We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.

SELECTION CRITERIA

Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.

AUTHORS' CONCLUSIONS

Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.

Pregnancy Outcome of Abnormal Nuchal Translucency: A Systematic Review

INTRODUCTION

Nuchal Translucency (NT) is the sonographic form of subcutaneous gathering of liquid behind the foetal neck in the first trimester of pregnancy. There is association of increased NT with chromosomal and non-chromosomal abnormalities.

AIM

The purpose of this systemic review was to review the pregnancy outcome of abnormal nuchal translucency.

MATERIALS AND METHODS

The present systematic review was conducted by searching English language articles from sources such as International Medical Sciences, Medline, Web of science, Scopus, Google Scholar, PubMed, Index Copernicus, DOAJ, EBSCO-CINAHL. Persian articles were searched from Iranmedex and SID sources. Related key words were "outcome", "pregnancy", "abnormal", and "Nuchal Translucency" (NT). All, randomized, descriptive, analytic-descriptive, case control study conducted during 1997-2015 were included.

RESULTS

Including duplicate articles, 95 related articles were found. After reviewing article titles, 30 unrelated article and abstracts were removed, and 65 articles were evaluated of which 30 articles were duplicate. Finally 22 articles were selected for final analysis. Exclusion criteria were, case studies and reports and quasi experimental designs. This evaluation has optioned negative relationship between nuchal translucency and pregnancy result. Rate of cardiac, chromosomal and other defects are correlated with increased NT≥2.5mm. Cardiac disease which were associated to the increased NT are heart murmur, systolic organic murmur, Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), tricuspid valve insufficiency and pulmonary valve insufficiency, Inferior Vena Cava (IVC) and Patent Ductus Arteriosus (PDA). The most common problems that related with increased NT were allergic symptoms.

CONCLUSION

According to this systematic review, increased NT is associated with various foetal defects. To verify the presence of malformations, birth defect consultations with a perinatologist and additional tests are required.

Combined screening test for trisomy 21 - is it as efficient as we believe?

OBJECTIVES

To compare two first-trimester screening strategies: traditional combined screening and the one based on ultrasound markers only. We investigated the effect of maternal age (MA) on the screening performance of both of these strategies.

METHODS

This was a prospective observational study based on a non-selected mixed-risk population of 11,653 women referred for first-trimester screening. The study population was divided in two groups: combined screening (CS) and ultrasound-based screening (US). Absolute risk was calculated to determine the influence of MA on screening performance.

RESULTS

The CS arm comprised 5145 subjects including 51 cases of trisomy 21 (T21), and the US arm comprised 5733 subjects including 87 subjects with T21. Seven hundred and seventy-five subjects were excluded from the study. For a false positive rate (FPR) of 3%, the detection rate (DR) of T21 in CS arm was 78% vs. 90% in US arm. For 5% FPR, DR was 84% and 94% in CS and US arm, respectively. MA had an influence on DR positive rates in CS: both DR and FPR for T21 increased with advance in MA.

CONCLUSIONS

The US protocol showed higher DR of T21 compared to the CS one. It may be considered as a viable alternative to CS for T21 where access to biochemical testing is limited.

Prenatal Risk Calculation (PRC) 3.0: An Extended DoE-Based First-Trimester Screening Algorithm Allowing For Early Blood Sampling

AIM

Both previous versions of the German PRC algorithm developed by our group for routine first-trimester screening relied on the assumption that maternal blood sampling and fetal ultrasonography are performed at the same visit of a pregnant women. In this paper we present an extension of our method allowing also for constellations where this synchronization is abandoned through preponing blood sampling to dates before 11 weeks of gestation.

METHODS

In contrast to the directly measured concentrations of the serum parameters PAPP-A and free ß-hCG, the logarithmically transformed values could be shown to admit the construction of reference bands covering the whole range from 16 to 84 mm CRL [corresponding to 63 to 98 days of gestation]. Prior to determining reference limits from which the DoEs for each individual patient had to be calculated, the log concentrations of all PAPP-A and free ß-hCG values were transformed once more using the calibration approach established in 1 for the elimination of the influence of maternal weight.

RESULTS

Although that part of the database which was available for estimating the reference bands for blood sampling times prior to 11 weeks of gestation was comparatively sparse (898 out of 186 215 pregnancies with euploid outcome), the key statistical characteristics of the extended risk-calculation procedure turned out to be very satisfactory. Using the same cutoff value of 1:150 for the posterior risks of trisomy 21 and 13/18, the overall FPR (false positive rate) for diagnosing a T21 was found to be 3.42%. The corresponding DTR (detection rate) was obtained to be 86.8% and thus exceeded the DTR attained by PRC 2.0 for trisomy 21. For trisomies 13 and 18, the proportions of patients with calculated posterior risks exceeding the cutoff value of 1:150 were obtained to be 1.60% (=FPR) and 86.4% (=DTR).

CONCLUSION

Transforming the measured concentrations of PAPP-A and free ß-hCG to the logarithmic scale allows one to extend the DoE-based algorithm developed by the FMF Germany for diagnosing trisomies 21 and 13/18 in such a way that it can be applied to constellations where blood sampling is done before 11 weeks of gestation.

Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

Objective

This study was designed to review the screening performance of combined test at the Ewha Womans University Mokdong hospital.

Methods

All women admitted for routine antenatal care between January 1st 2008 and December 31st 2012 with a known pregnancy outcome were included in this study, totaling 1,156 women with singleton pregnancies presenting at 10 to 13 weeks of gestation. Women were offered screening using a combination of maternal serum pregnancy-associated plasma protein-A, free β-human chorionic gonadotropin and fetal nuchal translucency thickness. Those with an estimated risk of ≥1 in 250 of carrying a fetus with trisomy 21 or ≥1 in 300 risk of trisomy 18 were offered genetic counseling with the option of an invasive diagnostic test.

Results

The median of gestational age was 11+3 weeks, the median of crown-rump length was 47.1 mm, and the median age of the women was 31 years. The detection rate was 80% for trisomy 21 (4 of 5) and 100% for trisomy 13 and 18 (all 2). The false-positive rate was 7.73% for trisomy 21 and 1.21% for trisomy 18.

Conclusion

This study was the first large population study performed with the aim of analyzing the performance of the combined test in Korea. This study demonstrated that the detection rates and other figures of the first trimester combined test are comparable to the results reported in other papers worldwide. Consequently, if strict conditions for good screening outcomes are achieved, the first trimester combined test might well be the earliest detectable screening, improving detection rates without increasing karyotyping or economic and other implications that inevitably ensue.

Analysis of first-trimester combined test results in preparation for a cell-free fetal DNA era

OBJECTIVE

To survey experience with the first-trimester combined test (FCT) for trisomy 21 (T21) in different risk score groups to determine the most useful clinical application of cell-free fetal DNA (cffDNA) screening.

METHODS

In a retrospective study, the records of FCT results obtained at a center in Turkey between January 2009 and January 2014 were reviewed. The FCT results and rates of uptake of invasive diagnostic testing were compared among different risk score groups.

RESULTS

FCT results were available for 4804 pregnancies; 276 (5.7%) had IDT results. Ten (72.7%) of 11 cases of T21 had a risk score of 1:300 or more. The IDT uptake rates were 54.5%, 51.9%, and 47.4% at risk scores of 1:100 or more, 1:200 or more, and 1:300 or more, respectively. In the group at intermediate risk (1:1001-1:3000), no pregnancy had an FCT result of both low pregnancy-associated plasma protein A and high free β-human chorionic gonadotropin, but 30 (3.9%) of 766 pregnancies had both advanced maternal age and high β-human chorionic gonadotropin.

CONCLUSION

cffDNA screening should be used to optimize IDT uptake in pregnancies with a risk score of 1:101-1:1000. The selective power of the FCT diminishes beyond the 1:1001 score and cffDNA screening cannot yet be recommended routinely.

Pregnancy Associated Plasma Protein-A and Placental Growth Factor in a Sub-Saharan African Population: A Nested Cross-Sectional Study

Background

Baseline distributions of pregnancy disorders’ biomarkers PlGF and PAPP-A levels are primarily based on Western European populations of Caucasian ethnicity. Differences in PAPP-A and PlGF concentrations by ethnicity have been observed, with increased levels in Afro-Caribbean, East Asian, and South Asian women. Baseline concentrations of sub-Saharan African women have not been evaluated.

Objectives

To investigate PlGF and PAPP-A in a sub-Saharan African population and assess the performance of existing reference values of PAPP-A and PlGF.

Methods

A nested cross-sectional study was conducted in two public hospitals in Accra, Ghana. Out of the original 1010 women enrolled in the cohort, 398 participants were eligible for inclusion with a normotensive singleton gestation and serum samples taken between 56–97 days of pregnancy. PAPP-A and PlGF concentrations were measured with an automated immunoassay. Multiple of the median (MoM) values corrected for gestation and maternal weight for PAPP-A and PlGF were calculated using reference values of a Dutch perinatal screening laboratory based on over 10.000 samples, and PlGF manufacturer reference values, respectively.

Results

The PAPP-A median MoM was 2.34 (interquartile range (IQR) 1.24–3.97). Median PlGF MoM was 1.25 (IQR 0.95–1.80). Median MoM values for PAPP-A and PlGF tended to be slightly different for various Ghanaian ethnic subgroups.

Conclusions

PAPP-A and PlGF MoM values appear to be substantially higher in a sub-Saharan African population compared to the Caucasian or Afro-Caribbean MoM values previously reported. The difference suggests the need for a specific correction factor for this population to avoid underestimation of risk for fetal aneuploidies or placental disorders when using PAPP-A and PlGF MoM for screening purposes.

Does Endometriosis Affect PAPP-A Concentration in First Trimester Fetal Screening Test?

Objective

Pregnancy-associated plasma protein A (PAPP-A) is a macromolecular glycoprotein. The peritoneal fluid of women affected by endometriosis shows a significant increase of PAPP-A levels. Given the important role of PAPP-A in first trimester screening test, we wondered if its presence in the peritoneal fluid of women with endometriosis could affect biochemical parameters of the test performed during pregnancy.

Methods

A prospective study enrolled 78 women with singleton pregnancy who performed combined test between 11 + 0 and 13 + 6 weeks of gestation: 25 women with previous histological diagnosis of endometriosis and 53 women without. All patients were sampled to determine PAPP-A concentrations. Serum levels of PAPP-A were expressed in UI/L and in MoM (multiples of median). The two groups – endometriosis women and non-endometriosis women – were compared in order to find a possible different concentration of serum PAPP-A.

Results

We found an increased concentration of both PAPP-A UI/L and PAPP-A MoM in deep endometriosis patients versus ovarian endometriosis with significant difference in PAPP-A MoM (p = 0.018). We also found a significant association between the stage of the disease and PAPP-A UI/L and MoM levels (PAPP-A UI/L p = 0.05, PAPP-A MoM p = 0.01).

Conclusions

Women with deep endometriosis show increased serum PAPP-A concentrations compared to women with ovarian endometriosis. Likewise, women with moderate or severe stage of the disease show increased serum PAPP-A concentrations compared to women with minimum or mild disease. This increase could affect first trimester aneuploidy screening test and endometriosis could represent a confounding factor in the calculation of aneuploidy risk.

Development of prenatal screening--A historical overview

The first prenatal screening test to be introduced was based on a single maternal serum marker of neural tube defects. Since then various prenatal screening concepts have been developed, the most successful being Down syndrome risk estimation using multiple serum and ultrasound markers. Today a completely new approach to aneuploidy screening is available based on maternal plasma cell-free DNA testing. This has the potential to markedly improve screening performance but routine testing is currently too expensive in a public health setting. However, it can be cost-effective when used in combination with existing multi-maker tests. Some are beginning to broaden prenatal screening to include pregnancy complications such as pre-eclampsia that can be prevented using soluble low-dose aspirin treatment started before 16 weeks of gestation. Prenatal screening for cardiac abnormalities, fragile X syndrome and recessive genetic disorders is underutilized and public health planners should considered a more widespread application of available methods.

Evidence-Based Revised View of the Pathophysiology of Preeclampsia

Preeclampsia is a life-threatening vascular disorder of pregnancy due to a failing stressed placenta. Millions of women risk death to give birth each year and globally each year, almost 300,000 lose their life in this process and over 500,000 babies die as a consequence of preeclampsia. Despite decades of research, we lack pharmacological agents to treat it. Maternal endothelial oxidative stress is a central phenomenon responsible for the preeclampsia phenotype of high maternal blood pressure and proteinuria. In 1997, it was proposed that preeclampsia arises due to the loss of VEGF activity, possibly due to elevation in anti-angiogenic factor, soluble Flt-1 (sFlt-1). Researchers showed that high sFlt-1 and soluble endoglin (sEng) elicit the severe preeclampsia phenotype in pregnant rodents. We demonstrated that heme oxygenase-1 (HO-1)/carbon monoxide (CO) pathway prevents placental stress and suppresses sFlt-1 and sEng release. Likewise, hydrogen sulphide (H₂S)/cystathionine-γ-lyase (Cth) systems limit sFlt-1 and sEng and protect against the preeclampsia phenotype in mice. Importantly, H₂S restores placental vasculature, and in doing so improves lagging fetal growth. These molecules act as the inhibitor systems in pregnancy and when they fail, preeclampsia is triggered. In this review, we discuss what are the hypotheses and models for the pathophysiology of preeclampsia on the basis of Bradford Hill causation criteria for disease causation and how further in vivo experimentation is needed to establish 'proof of principle'. Hypotheses that fail to meet the Bradford Hill causation criteria include abnormal spiral artery remodelling and inflammation and should be considered associated or consequential to the disorder. In contrast, the protection against cellular stress hypothesis that states that the protective pathways mitigate cellular stress by limiting elevation of anti-angiogenic factors or oxidative stress and the subsequent clinical signs of preeclampsia appear to fulfil most of Bradford Hill causation criteria. Identifying the candidates on the roadmap to this pathway is essential in developing diagnostics and therapeutics to target the pathogenesis of preeclampsia.

Impact of Including or Removing Nuchal Translucency Measurement on the Detection and False-Positive Rates of First-Trimester Down Syndrome Screening

INTRODUCTION

First-trimester Down syndrome (DS) screening combining maternal age, serum markers (pregnancy-associated plasma protein-A and beta-human chorionic gonadotropin) and nuchal translucency (NT) gives an 85% detection rate for a 5% false-positive rate. These results largely depend on quality assessment of biochemical markers and of NT. In routine practice, despite an ultrasound quality control organization, NT images can be considered inadequate. The aim of the study was to evaluate the consequences for risk calculation when NT measurement is not taken into account.

MATERIAL AND METHOD

Comparison of detection and false-positive rates of first-trimester DS screening (PerkinElmer, Turku, Finland), with and without NT, based on a retrospective study of 117,126 patients including 274 trisomy 21-affected fetuses. NT was measured by more than 3,000 certified sonographers.

RESULTS

There was no significant difference in detection rates between the two strategies including or excluding NT measurement (86.7 vs. 81.8%). However, there was a significant difference in the false-positive rates (2.23 vs. 9.97%, p < 0.001).

DISCUSSION

Sonographers should be aware that removing NT from combined first-trimester screening would result in a 5-fold increase in false-positive rate to maintain the expected detection rates. This should be an incentive for maintaining quality in NT measurement.

Screening performances of abnormal first-trimester ductus venosus blood flow and increased nuchal translucency thickness in detection of major heart defects

OBJECTIVE

The aim of this study was to evaluate the screening performances of abnormal ductus venosus (DV) blood flow for the detection of heart defects in chromosomally normal fetuses with increased nuchal translucency (NT) thickness at 11-13 + 6 weeks' gestational in a population of singleton pregnancies.

METHODS

During an 8-year period, all singleton pregnancies from 11 + 0 to 13 + 6 weeks were scanned for NT and DV blood flow assessment. Two groups of cases with abnormal NT were evaluated: NT ≥ 95th and NT ≥ 99th centile. DV waveforms were considered to be abnormal if the a-wave was reversed or absent (R/A).

RESULTS

Addition of DV R/A a-wave to either NT ≥ 95th or NT ≥ 99th percentile increased specificity (p < 0.001 and p < 0.001, respectively), but not screening performances in detection of major heart defects (p = 0.73 and p = 0.91, respectively). Combination of DV R/A a-wave with NT ≥ 95th or NT ≥ 99th centile correlated with right heart defects (p = 0.024 and p = 0.013, respectively).

CONCLUSIONS

In chromosomally normal fetuses, addition of abnormal DV a-wave to increased NT does not improve screening performances of NT in detection of major hearts defects in first trimester. However, there is correlation of such parameter with right heart defects and AV septal defects.

Informed Choice for Participation in Down Syndrome Screening: Development and Content of a Web-Based Decision Aid

Background

In Denmark, all pregnant women are offered screening in early pregnancy to estimate the risk of having a fetus with Down syndrome. Pregnant women participating in the screening program should be provided with information and support to allow them to make an informed choice. There is increasing interest in the use of Web-based technology to provide information and digital solutions for the delivery of health care.

Objective

The aim of this study was to develop an eHealth tool that contained accurate and relevant information to allow pregnant women to make an informed choice about whether to accept or reject participation in screening for Down syndrome.

Methods

The development of the eHealth tool involved the cooperation of researchers, technology experts, clinicians, and users. The underlying theoretical framework was based on participatory design, the International Patient Decision Aid Standards (IPDAS) Collaboration guide to develop a patient decision aid, and the roadmap for developing eHealth technologies from the Center for eHealth Research and Disease Management (CeHRes). The methods employed were a systematic literature search, focus group interviews with 3 care providers and 14 pregnant women, and 2 weeks of field observations. A qualitative descriptive approach was used in this study.

Results

Relevant themes from pregnant women and care providers with respect to information about Down syndrome screening were identified. Based on formalized processes for developing patient decision aids and eHealth technologies, an interactive website containing information about Down syndrome, methods of screening, and consequences of the test was developed. The intervention was based on user requests and needs, and reflected the current hospital practice and national guidelines.

Conclusions

This paper describes the development and content of an interactive website to support pregnant women in making informed choices about Down syndrome screening. To develop the website, we used a well-structured process based on scientific evidence and involved pregnant women, care providers, and technology experts as stakeholders. To our knowledge, there has been no research on the combination of IPDAS standards and the CeHRes roadmap to develop an eHealth tool to target information about screening for Down syndrome.

Reasons for declining extended information visit on prenatal screening among pregnant women and their partners

OBJECTIVE

A two-step model on information on prenatal screening consists of brief information at the first visit at the Maternal Health Care Centre and an offer of extended information at a separate visit. There is a lack of knowledge why some pregnant women and their partners refrain from the extended information visit. The aim of this study was to explore their reasons.

METHOD

Eight qualitative interviews were analyzed using Interpretive Description.

RESULTS

In the first theme 'From an individual view', the interviewees saw the invitation from their own points of view. They refrained because they did not want to receive any more information or had taken an individual position against chromosomal testing. In the theme, 'From a societal view', the interviewees perceived the offer as part of a societal view on prenatal screening that they could not support.

CONCLUSION

The findings show that these interviewees' reasons of declining an extended information visit are multidimensional and influenced by different views, from both an individual perspective and a more societal one. Health care professionals should be aware that some persons could have a different view on health care services and could be reluctant to accept offered services.

How Effective Is First-Trimester Screening for Trisomy 21 Based on Ultrasound Only?

Objective: To evaluate the most common first-trimester ultrasound features of fetuses with trisomy 21 (T21) and to examine the screening performance for Down syndrome (DS) using only ultrasound-based protocols. To investigate whether maternal age (MA) has an impact on the efficacy of the ultrasound-based screening methods. Methods: In a prospective study, 6,265 patients were examined. Two ultrasound-based risk calculation protocols were applied: ‘NT' (based on nuchal translucency) and ‘NT+' (based on NT and secondary markers). Results: A total of 5,696 patients were enrolled for analysis; 84 subjects with T21 were identified. Combinations of abnormal ultrasound markers were observed in only 1.2% of euploid fetuses compared to 71.5% of fetuses with T21. Among 17.9% of DS cases with cardiac anomaly, 14.3% comprised atrioventricular septal defects. For a false-positive rate of 3%, the detection rates of T21 were 73.8 and 91.7% for the ‘NT' and ‘NT+' protocols, respectively. The efficacy of both methods was affected by MA. Conclusions: Most of the fetuses with DS demonstrate a combination of ultrasound markers of aneuploidy in the first trimester. The ‘NT+' protocol is efficient and provides comparable performance as a combined screening test. It is a valuable method, especially when the access to biochemical analysis is restricted.

First Trimester Noninvasive Prenatal Diagnosis: A Computational Intelligence Approach

The objective of this study is to examine the potential value of using machine learning techniques such as artificial neural network (ANN) schemes for the noninvasive estimation, at 11-13 weeks of gestation, the risk for euploidy, trisomy 21 (T21), and other chromosomal aneuploidies (O.C.A.), from suitable sonographic, biochemical markers, and other relevant data. A database(1) (1)The dataset can become available for academic purposes by communicating directly with the authors.