Combined first-trimester screening and invasive diagnostics for atypical chromosomal aberrations: Danish nationwide data on prenatal profiles and detection compared with NIPT

OBJECTIVE

To examine the prenatal profiles of pregnancies affected by an atypical chromosomal aberration, focusing on pathogenic copy number variants (pCNVs). Further, we wanted to quantify the performance of combined first-trimester screening (cFTS) and a second-trimester anomaly scan in detecting these conditions. Finally, we aimed to estimate the consequences of a policy of using non-invasive prenatal testing (NIPT) rather than invasive testing with chromosomal microarray (CMA) to manage pregnancies identified as high risk from cFTS.

METHODS

A retrospective review of the Danish fetal medicine database identified all pregnant women who had cFTS and a trisomy 21 risk-assessment between January 1, 2008, and December 31, 2018. Chromosomal aberrations diagnosed prenatally, postnatally, or from fetal tissue following pregnancy loss or termination of pregnancy (TOP) were identified. Chromosomal aberrations were grouped into one of six categories: 1) Triploidy; 2) Common trisomies (trisomies 21, 18, and 13); 3) Monosomy X; 4) Other sex chromosome aberrations (SCAs); 5) pCNVs; and 6) Rare autosomal trisomies (RATs) and mosaicisms. The prevalence of each aberration-category was stratified by the individual cFTS markers and risk estimate, and the size of each pCNV diagnosed from CMA was calculated.

RESULTS

We included data on 565,708 pregnancies of which 3,982 were diagnosed with a fetal chromosomal aberration (0.70%). cFTS performed well in identifying triploidies (86%), monosomy X (92%), atypical SCAs (58%), and RATs and mosaicisms (70%). pCNVs comprised 28% (n = 1,091) of the chromosomal aberrations diagnosed overall, and the prevalence increased during the study period with more prenatal chromosomal microarray analysis being performed. In pregnancies with maternal age <30 years, NT <95th percentile, PAPP-A MoM ≥ 1, or trisomy 21 risk ≥1 in 1000, the prevalence of pCNVs significantly exceeded the prevalence of trisomies 21, 18, and 13. Pregnancies affected by a pCNV had significantly increased nuchal translucency thickness (NT) and decreased maternal biomarkers pregnancy associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG) compared with unaffected pregnancies. However, only 23% of these pregnancies screened positive from cFTS and 51% were not detected until after birth. Amongst high-risk pregnancies diagnosed with a chromosomal aberration, pCNVs comprised 14% and when other atypical aberrations were considered, conventional NIPT (screening for trisomies 21, 18, and 13, and monosomy X) would miss 28% of all pathogenic aberrations diagnosed following a high-risk cFTS result. Thus, 1 in 26 pregnancies at high-risk following cFTS would be affected by a chromosomal aberration despite a normal conventional NIPT result. In a contingent screening model with NIPT provided for the "intermediate" risk group (T21 risk of 1 in 100-300), 50% of the aberrations would be missed. In our cohort, 80% of the pCNVs diagnosed were <5Mb and therefore not detectable using current forms of "genome wide" NIPT.

CONCLUSION

As a by-product to screening for trisomies 21, 18, and 13, most triploidies and the majority of atypical SCAs, RATs, and mosaicisms are detected before birth. However, only 23% of pCNVs are high-risk from cFTS and only half are diagnosed before birth. Replacing invasive testing with NIPT for high-risk pregnancies would substantially decrease the first-trimester detection of pathogenic chromosomal anomalies. This article is protected by copyright. All rights reserved.

Prenatal detection of orofacial clefts in Denmark from 2009 to 2018

OBJECTIVE

To investigate the overall and type-specific prenatal detection rates (DRs) of orofacial clefts in a national cohort in Denmark.

METHODS

This study was based on data from the Danish Fetal Medicine Database and included all fetuses and children from singleton pregnancies diagnosed with an orofacial cleft prenatally and/or postnatally between 2009 and 2018. The types of cleft included unilateral, bilateral or median cleft lip (CL); unilateral, bilateral or median cleft lip with secondary cleft palate (CLP); and cleft palate (CP). The clefts were grouped as cleft lip with or without cleft palate (CL(P)) or as all clefts (including CP). All cases with discordance between prenatal and postnatal diagnoses were validated in the local patient files (Astraia). Cases without prenatal validation of the postnatal diagnosis were marked as undetected. Postnatally diagnosed cases with a strong prenatal suspicion of a cleft but without an International Classification of Diseases-10 code were registered as prenatally detected. Termination of pregnancy and intrauterine death were registered as true positives even if no autopsy could be performed. Liveborn cases with a prenatal diagnosis but without a postnatal validation were excluded.

RESULTS

A total of 994 cases were included in the study, of which 933 were liveborn. The prevalence of orofacial cleft was 1.6 per 1000 live births. There were no differences in the baseline characteristics between detected and undetected cases. The DR for CL(P) was 71.7% (95% CI, 64.8-78.9%), with an increase from 60.0% in 2009 to 73.0% in 2018 (P = 0.018). The type-specific DRs for the entire period were 56.4% (95% CI, 45.0-67.6%) for unilateral CL; 76.6% (95% CI, 71.7-82.9%) for unilateral CLP; 70.5% (95% CI, 52.1-87.6%) for bilateral CL; 82.3% (95% CI, 70.6-93.6%) for bilateral CLP; 0% (0/6) for median CL; 75.0% (3/4) for median CLP; and 3.3% (95% CI, 0.6-5.7%) for CP. A total of 20.9% (208/994) of the cases had associated findings, of which 33.2% (69/208) were genetic aberrations.

CONCLUSIONS

The DR for CL(P) has improved in Denmark over the last decade. The DR for CLP is high, with the highest DR for bilateral CLP. However, prenatal detection of CP remains a challenge. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Quadruplet pregnancy outcome with and without fetal reduction: Danish national cohort study (2008-2018) and comparison with dichorionic twins

OBJECTIVES

To perform a nationwide study of quadrichorionic quadriamniotic (QCQA) quadruplet pregnancies and to compare the pregnancy outcome in those undergoing fetal reduction with non-reduced quadruplets and dichorionic diamniotic (DCDA) twin pregnancies from the same time period.

METHODS

This was a retrospective Danish national register-based study performed using data from the national Danish Fetal Medicine Database, which included all QCQA quadruplets and all non-reduced DCDA twin pregnancies with an estimated due date between 2008 and 2018. The primary outcome measure was a composite of adverse pregnancy outcomes, including pregnancy loss or intrauterine death of one or more fetuses. Secondary outcomes included gestational age at delivery, the number of liveborn children, preterm delivery before 28, 32 and 37 gestational weeks and birth weight. Data on pregnancy complications and baseline characteristics were also recorded. Outcomes were compared between reduced and non-reduced quadruplet pregnancies, and between DCDA pregnancies and quadruplet pregnancies reduced to twins. A systematic literature search was performed to describe and compare previous results with our findings.

RESULTS

Included in the study were 33 QCQA quadruplet pregnancies, including three (9.1%) non-reduced pregnancies, 28 (84.8%) that were reduced to twin pregnancy and fewer than three (6.1%) that were reduced to singleton pregnancy, as well as 9563 DCDA twin pregnancies. Overall, the rate of adverse pregnancy outcome was highest in non-reduced quadruplets (66.7%); it was 50% in quadruplets reduced to singletons and 10.7% in quadruplets reduced to twins. The proportion of liveborn infants overall was 91.1% of the total number expected to be liveborn in quadruplet pregnancies reduced to twins. This was statistically significantly different from 97.6% in non-reduced dichorionic twins (P = 0.004), and considerably higher than 58.3% in non-reduced quadruplets. The rates of preterm delivery < 28, < 32 and < 37 weeks were decreased in quadruplets reduced to twins compared with those in non-reduced quadruplet pregnancies. Quadruplets reduced to twins did not achieve equivalent pregnancy outcomes to those of DCDA twins.

CONCLUSION

This national study of QCQA quadruplets has shown that multifetal pregnancy reduction improves pregnancy outcome, including a decreased rate of preterm delivery and higher proportion of liveborn children. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

AI supported fetal echocardiography with quality assessment

This study aimed to develop a deep learning model to assess the quality of fetal echocardiography and to perform prospective clinical validation. The model was trained on data from the 18-22-week anomaly scan conducted in seven hospitals from 2008 to 2018. Prospective validation involved 100 patients from two hospitals. A total of 5363 images from 2551 pregnancies were used for training and validation. The model's segmentation accuracy depended on image quality measured by a quality score (QS). It achieved an overall average accuracy of 0.91 (SD 0.09) across the test set, with images having above-average QS scoring 0.97 (SD 0.03). During prospective validation of 192 images, clinicians rated 44.8% (SD 9.8) of images as equal in quality, 18.69% (SD 5.7) favoring auto-captured images and 36.51% (SD 9.0) preferring manually captured ones. Images with above average QS showed better agreement on segmentations (p < 0.001) and QS (p < 0.001) with fetal medicine experts. Auto-capture saved additional planes beyond protocol requirements, resulting in more comprehensive echocardiographies. Low QS had adverse effect on both model performance and clinician's agreement with model feedback. The findings highlight the importance of developing and evaluating AI models based on 'noisy' real-life data rather than pursuing the highest accuracy possible with retrospective academic-grade data.

Incidence of neonatal morbidity in small-for-gestational-age twins based on singleton and twin charts

OBJECTIVE

To compare morbidity, as measured by length of stay in the neonatal intensive care unit (NICU), in twin and singleton gestations classified as small-for-gestational age (SGA) according to estimated fetal weight < 10th percentile on twin or singleton growth charts.

METHODS

NICU length of stay was compared in 1150 twins and 29 035 singletons that underwent ultrasound assessment between 35 + 0 and 36 + 6 weeks' gestation. Estimated fetal weight was obtained from measurements of head circumference, abdominal circumference and femur length using the Hadlock formula. Gestational age was derived from the first-trimester crown-rump length measurement, using the larger of the two twins. Singletons and twins were compared in terms of NICU admission rate and length of stay according to classification as SGA by the Fetal Medicine Foundation singleton and twin reference distributions.

RESULTS

The overall proportions of twins and singletons admitted to NICU were similar (7.3% vs 7.4%), but twins tended to have longer lengths of stay in NICU (≥ 7 days: 2.4% vs 0.8%; relative risk (RR), 3.0 (95% CI, 1.6-4.4)). Using the singleton chart, a higher proportion of twins were classified as SGA compared with singletons (37.6% vs 7.0%). However, the proportion of SGA neonates entering NICU was similar (10.2% for twins and 10.1% for singletons) and the proportion of SGA neonates spending ≥ 7 days in NICU was substantially higher for twins compared with singletons (3.7% vs 1.4%; RR, 2.6 (95% CI, 1.4-4.7)).

CONCLUSIONS

When singleton charts are used to define SGA in twins and in singletons, there is a greater degree of growth-related neonatal morbidity amongst SGA twins compared with SGA singletons. Consequently, singleton charts do not inappropriately overdiagnose fetal growth restriction in twins and they should be used for monitoring fetal growth in both twins and singletons. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Medicine Foundation charts for fetal growth in twins

OBJECTIVE

To derive reference distributions of estimated fetal weight (EFW) in twins relative to singletons.

METHODS

Gestational-age- and chorionicity-specific reference distributions for singleton percentiles and EFW were fitted to data on 4391 twin pregnancies with two liveborn fetuses from four European centers, including 3323 dichorionic (DC) and 1068 monochorionic diamniotic (MCDA) twin pregnancies. Gestational age was derived using the larger of the two crown-rump length measurements obtained during the first trimester of pregnancy. EFW was obtained from ultrasound measurements of head circumference, abdominal circumference and femur length using the Hadlock formula. Singleton percentiles were obtained using the Fetal Medicine Foundation population weight charts for singleton pregnancies. Hierarchical models were fitted to singleton Z-scores with autoregressive terms for serial correlations within the same fetus and between twins from the same pregnancy. Separate models were fitted for DC and MCDA twins.

RESULTS

Fetuses from twin pregnancies tended to be smaller than singletons at the earliest gestational ages (16 weeks for MCDA and 20 weeks for DC twins). This was followed by a period of catch-up growth until around 24 weeks. After that, both DC and MCDA twins showed reduced growth. In DC twins, the EFW corresponding to the 50th percentile was at the 50th percentile of singleton pregnancies at 23 weeks, the 43rd percentile at 28 weeks, the 32nd percentile at 32 weeks and the 22nd percentile at 36 weeks. In MCDA twins, the EFW corresponding to the 50th percentile was at the 36th percentile of singleton pregnancies at 24 weeks, the 29th percentile at 28 weeks, the 19th percentile at 32 weeks and the 12th percentile at 36 weeks.

CONCLUSIONS

In DC and, to a greater extent, MCDA twin pregnancies, fetal growth is reduced compared with that observed in singleton pregnancies. Furthermore, after 24 weeks, the divergence in growth trajectories between twin and singleton pregnancies becomes more pronounced as gestational age increases. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Decoding 22q11.2: prenatal profiling and first-trimester risk assessment in Danish nationwide cohort

OBJECTIVES

To examine the distribution of nuchal translucency thickness (NT), free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) in pregnancies with a fetal 22q11.2 aberration. Furthermore, the performance of combined first-trimester screening (cFTS) and a new risk algorithm targeting 22q11.2 deletions in detecting affected pregnancies was evaluated. Finally, prenatal malformations and pregnancy outcome were assessed.

METHODS

This was a nationwide registry-based cohort study of all pregnancies that underwent prenatal screening with a due date between January 2008 and December 2018 in Denmark. All cases with a fetal 22q11.2 deletion or duplication (hg19 chr22:18.9mio-25.0mio) diagnosed pre- or postnatally or following pregnancy loss or termination of pregnancy were retrieved from the Danish Cytogenetic Central Register and linked with pregnancy data from the Danish Fetal Medicine Database. Fetal and maternal characteristics, including cFTS results and pregnancy outcome, of pregnancies with any 22q11.2 deletion or duplication (LCR22-A to -H) and pregnancies with a classic deletion or duplication (LCR22-A to -D) diagnosed by chromosomal microarray were compared with those of a chromosomally normal reference group. A risk algorithm was developed for assessing patient-specific risks for classic 22q11.2 deletions based on NT, PAPP-A and β-hCG. Detection rates and false-positive rates at different risk cut-offs were calculated.

RESULTS

We included data on 143 pregnancies with a fetal 22q11.2 aberration, of which 97 were deletions (54 classic) and 46 were duplications (32 classic). NT was significantly increased in fetuses with a classic deletion (mean, 1.89 mm), those with any deletion (mean, 1.78 mm) and those with any duplication (mean, 1.86 mm) compared to the reference group (mean, 1.65 mm). β-hCG multiples of the median (MoM) was decreased in all 22q11.2 subgroups compared with the reference group (mean, 1.02) and reached significance in pregnancies with a classic deletion and those with any deletion (mean, 0.77 and 0.71, respectively). PAPP-A MoM was significantly decreased in pregnancies with a classic duplication and those with any duplication (mean, 0.57 and 0.63, respectively), and was significantly increased in pregnancies with a classic deletion and those with any deletion (mean, 1.34 and 1.16, respectively), compared to reference pregnancies (mean, 1.01). The screen-positive rate by cFTS was significantly increased in pregnancies with a classic deletion (13.7%), any deletion (12.5%), a classic duplication (46.9%) or any duplication (37.8%) compared to the reference group (4.5%). A risk algorithm targeting classic 22q11.2 deletions more than doubled the prenatal detection rate of classic 22q11.2 deletions, but with a substantial increase in the false-positive rate. Structural malformations were detected in 41%, 35%, 17% and 25% of the pregnancies with a classic deletion, any deletion, classic duplication or any duplication, respectively. Pregnancy loss occurred in 40% of pregnancies with a classic deletion and 5% of those with a classic duplication diagnosed prenatally or following pregnancy loss.

CONCLUSIONS

The distribution of cFTS markers in pregnancies with a classic 22q11.2 duplication resembles that of the common trisomies, with decreased levels of PAPP-A. However, classic 22q11.2 deletions are associated with increased levels of PAPP-A, which likely limits early prenatal detection using the current cFTS risk algorithm. The scope for improving early detection of classic 22q11.2 deletions using targeted risk algorithms based on NT, PAPP-A and β-hCG is limited. This demonstrates the capability, but also the limitations, of cFTS markers in detecting atypical chromosomal anomalies, which is important knowledge when designing new prenatal screening programs. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Atypicality index as an add-on to combined first-trimester screening for chromosomal aberrations

OBJECTIVES

To compute a set of atypicality indices from combined first-trimester screening (cFTS) markers and second-trimester estimated fetal weight (EFW), and to demonstrate their potential in identifying pregnancies at either reduced or increased risks of chromosomal aberrations following a low-risk cFTS result.

METHODS

The atypicality index quantifies the unusualness of an individual set of measurements relative to a reference distribution and can be computed from any variables or measurements available. A score of 0% on the atypicality index represents the most typical profiles, while a score of 100% indicates the highest level of atypicality. From the Danish Fetal Medicine Database, we retrieved data on all pregnant women seen for cFTS in Central Denmark Region between January 2008 and December 2018. All pregnancies with a cytogenetic or molecular analysis obtained prenatally, postnatally, or following pregnancy loss or termination of pregnancy were identified. A first-trimester atypicality index (AcFTS ) was computed from nuchal translucency (NT) thickness, maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Further, a second trimester index (AcFTS+EFW ) was computed from cFTS markers and estimated fetal weight (EFW) estimated at a routine second-trimester anomaly scan. All pregnancies were stratified into subgroups based on their atypicality levels and their cFTS risk estimates. The risk of chromosomal aberrations in each subgroup was then compared with the overall prevalence, and a graphical presentation of multivariate measurement profiles was introduced.

RESULTS

We retrieved data on 145,955 singleton pregnancies, of which 9824 (6.7%) were genetically examined. Overall, 1 in 122 of all pregnancies seen for cFTS (0.82% [95% CI 0.77-0.87%]) were affected by a fetal chromosomal aberration and in screen-negative pregnancies (cFTS T21 risk <1 in 100 and/or T18/13 risk <1 in 50), 0.41% [95% CI 0.38-0.44%] were affected. In screen-negative pregnancies with a typical first-trimester profile (AcFTS <80% ), the risk of chromosomal aberrations was significantly reduced (0.28%) compared to the overall risk. The risk of chromosomal aberrations increased with higher atypicality index to 0.49% (AcFTS [80-90%) ), 1.52% (AcFTS [90-99%) ), and 4.44% (AcFTS [>99%) ) and was significantly increased in the two most atypical subgroups. The same applied for the second trimester atypicality index (AcFTS+EFW ) with risks of chromosomal aberrations of 0.76% and 4.16% in the two most atypical subgroups (AcFTS+EFW [90-99%) and AcFTS+EFW >99% , respectively).

CONCLUSIONS

As an add-on to cFTS, the atypicality index identifies women with typical measurement profiles which may act as reassurance, whereas atypical profiles may warrant specialist referral and further investigations. In pregnancies at low risk from cFTS but with a highly atypical distribution of NT, PAPP-A, and β-hCG, the risk of a chromosomal aberration is substantially increased. The atypicality index optimizes the interpretation of pre-existing prenatal screening profiles and is not limited to cFTS markers or EFW. This article is protected by copyright. All rights reserved.

First-trimester prediction of preterm prelabour rupture of membranes incorporating cervical length measurement

OBJECTIVES

To examine early pregnancy risk factors for preterm prelabour rupture of membranes (PPROM) and develop a predictive model.

STUDY DESIGN

Retrospective analysis of a cohort of mixed-risk singleton pregnancies screened in the first and second trimesters in three Danish tertiary fetal medicine centres, including a cervical length measurement at 11-14 weeks, at 19-21 weeks and at 23-24 weeks of gestation. Univariable and multivariable logistic regression analyses were employed to identify predictive maternal characteristics, biochemical and sonographic factors. Receiver operating characteristic (ROC) curve analysis was used to determine predictors for the most accurate model.

RESULTS

Of 3477 screened women, 77 (2.2%) had PPROM. Maternal factors predictive of PPROM in univariable analysis were nulliparity (OR 2.0 (95% CI 1.2-3.3)), PAPP-A < 0.5 MoM (OR 2.6 (1.1-6.2)), previous preterm birth (OR 4.2 (1.9-8.9)), previous cervical conization (OR 3.6 (2.0-6.4)) and cervical length ≤ 25 mm on transvaginal imaging (first-trimester OR 15.9 (4.3-59.3)). These factors all remained statistically significant in a multivariable adjusted model with an AUC of 0.72 in the most discriminatory first-trimester model. The detection rate using this model would be approximately 30% at a false-positive rate of 10%. Potential predictors such as bleeding in early pregnancy and pre-existing diabetes mellitus affected very few cases and could not be formally assessed.

CONCLUSIONS

Several maternal characteristics, placental biochemical and sonographic features are predictive of PPROM with moderate discrimination. Larger numbers are required to validate this algorithm and additional biomarkers, not currently used for first-trimester screening, may improve model performance.

Atypicality index: avoiding false reassurance in prenatal screening

OBJECTIVE

To demonstrate the application of the atypicality index as an adjunct to first-trimester risk assessment for major trisomies by the combined test.

METHODS

This was a study of 123 998 Danish women with a singleton pregnancy who underwent routine first-trimester screening, including risk assessment for major trisomies. An atypicality index, which is a measure of the degree to which a profile is atypical, was produced for measurements of fetal nuchal translucency thickness and maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A. The incidence of adverse pregnancy outcome, including miscarriage, intrauterine death and termination of pregnancy, was tabulated according to the screening result and atypicality index.

RESULTS

In pregnancies with low risk and those with high risk for major trisomies according to the combined screening test, the incidence of adverse pregnancy outcome increased with increasing atypicality index. In pregnancies with a low risk for trisomies and atypicality index of ≥ 99%, the incidence of adverse outcome was 5.1 (95% CI, 3.4-7.6) times higher compared with that in low-risk pregnancies with a typical measurement profile, reflected by an atypicality index of < 80%. Similarly, in high-risk pregnancies, the incidence of adverse outcome was 7.9 (95% CI, 4.4-14.5) times higher in those with an atypicality index of ≥ 99% compared to those with an atypicality index of < 80%. Using individual profile plots, we were able to demonstrate a transparent and intuitive method for visualization of multiple variables, which can help interpret the individual combination of measurements and level of atypicality.

CONCLUSIONS

In pregnancies undergoing first-trimester combined screening and classified as being at low risk for major trisomies, profiles that are typical of pregnancies with normal outcome provide additional reassurance, whereas those with an atypical profile may warrant further investigation. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Trends in Non-invasive Prenatal Screening and Invasive Testing in Denmark (2000-2019) and Israel (2011-2019)

Introduction: Following the wide distribution of non-invasive prenatal genetic screening (NIPS), numerous studies have reported a decline in total invasive tests in the recent years, up to 50–70% in some countries. However, in Denmark and Israel we have not experienced these declines. The objective of our study was to evaluate the trends in NIPS and chromosomal microarray analysis (CMA) use in Denmark and Israel.

Methods: This retrospective study was performed by data acquisition from the Danish Cytogenetics Central Registry throughout the years 2000–2019, and Israeli Public Health Services, Ministry of Health computerized database (from 2011).

Results: Of the 1,243,956 live births registered in Denmark over the years 2000–2019, a relatively steady level of invasive testing around 6% was noted since 2004, as opposed to 13.0% in Israel based on 1,594,962 live births between 2011 and 2019. The average uptake of NIPS was 1.1 ± 0.5% in Denmark vs. 4.3% in Israel (2013–2019). Relatively steady rates of invasive testing were noted in both countries, compared to a slight decline in NIPS in the recent years.

Discussion: The recent decrease in the rates of invasive testing in the NIPS era was not observed in Denmark or in Israel. These results imply that Danish and Israeli women and/or health providers might favor the high resolution and yield of CMA testing over the non-invasiveness of NIPS. We explore and discuss this phenomenon, based on five central factors.

Prenatal cardiac biometry and flow assessment in fetuses with bicuspid aortic valve at 20 weeks' gestation: multicenter cohort study

OBJECTIVE

To investigate prenatal changes in cardiac biometric and flow parameters in fetuses with bicuspid aortic valve (BAV) diagnosed neonatally compared with controls with normal cardiac anatomy.

METHODS

This analysis was conducted as part of the Copenhagen Baby Heart Study, a multicenter cohort study of 25 556 neonates that underwent second-trimester anomaly scan at 18 + 0 to 22 + 6 weeks' gestation and neonatal echocardiography within 4 weeks after birth, in Copenhagen University Hospital Herlev, Hvidovre Hospital and Rigshospitalet in greater Copenhagen, between April 2016 and October 2018. From February 2017 (Rigshospitalet) and September 2017 (Herlev and Hvidovre hospitals), the protocol for second-trimester screening of the heart was extended to include evaluation of the four-chamber view, with assessment of flow across the atrioventricular valves, sagittal view of the aortic arch and midumbilical artery and ductus venosus pulsatility indices. All images were evaluated by two investigators, and cardiac biometric and flow parameters were measured and compared between cases with BAV and controls. All cases with neonatal BAV were assessed by a specialist. Maternal characteristics and first- and second-trimester biomarkers were also compared between the two groups.

RESULTS

Fifty-five infants with BAV and 8316 controls with normal cardiac anatomy were identified during the study period and assessed using the extended prenatal cardiac imaging protocol. There were three times as many mothers who smoked before pregnancy in the group with BAV as in the control group (9.1% vs 2.7%; P = 0.003). All other baseline characteristics were similar between the two groups. Fetuses with BAV, compared with controls, had a significantly larger diameter of the aorta at the level of the aortic valve (3.1 mm vs 3.0 mm (mean difference, 0.12 mm (95% CI, 0.03-0.21 mm))) and the pulmonary artery at the level of the pulmonary valve (4.1 mm vs 3.9 mm (mean difference, 0.15 mm (95% CI, 0.03-0.28 mm))). Following conversion of the diameter measurements of the aorta and pulmonary artery to Z-scores and Bonferroni correction, the differences between the two groups were no longer statistically significant. Pregnancy-associated plasma protein-A (PAPP-A) multiples of the median (MoM) was significantly lower in the BAV group than in the control group (0.85 vs 1.03; P = 0.04).

CONCLUSIONS

Our findings suggest that fetuses with BAV may have a larger aortic diameter at the level of the aortic valve, measured in the left-ventricular-outflow-tract view, and a larger pulmonary artery diameter at the level of the pulmonary valve, measured in the three-vessel view, at 20 weeks' gestation. Moreover, we found an association of maternal smoking and low PAPP-A MoM with BAV. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Consensus on Training and Assessment of Competence in Performing Chorionic Villus Sampling and Amniocentesis: An International Delphi Survey

INTRODUCTION

The aim of this study was to obtain expert consensus on the content of a curriculum for learning chorionic villus sampling (CVS) and amniocentesis (AC) and the items of an assessment tool to evaluate CVS and AC competence.

METHODS

We used a 3-round iterative Delphi process. A steering committee supervised all processes. Seven international collaborators were identified to expand the breadth of the study internationally. The collaborators invited fetal medicine experts to participate as panelists. In the first round, the panelists suggested content for a CVS/AC curriculum and an assessment tool. The steering committee organized and condensed the suggested items and presented them to the panelists in round 2. In the second round, the panelists rated and commented on the suggested items. The results were processed by the steering committee and presented to the panelists in the third round, where final consensus was obtained. Consensus was defined as support by more than 80% of the panelists for an item.

RESULTS

Eighty-six experts agreed to participate in the study. The panelists represented 16 countries across 4 continents. The final list of curricular content included 12 theoretical and practical items. The final assessment tool included 11 items, systematically divided into 5 categories: pre-procedure, procedure, post-procedure, nontechnical skills, and overall performance. These items were provided with behavioral scale anchors to rate performance, and an entrustment scale was used for the final overall assessment.

CONCLUSION

We established consensus among international fetal medicine experts on content to be included in a CVS/AC curriculum and on an assessment tool to evaluate CVS/AC skills. These results are important to help transition current training and assessment methods from a time- and volume-based approach to a competency-based approach which is a key step in improving patient safety and outcomes for the 2 most common invasive procedures in fetal medicine.

Crown-rump length measurement error: impact on assessment of growth

OBJECTIVE

To examine the impact of first-trimester crown-rump length (CRL) measurement error on the interpretation of estimated fetal weight (EFW) and classification of fetuses as small-, large- or appropriate-for-gestational age on subsequent growth scans.

METHODS

We examined the effects of errors of ± 2, ± 3 and ± 4 mm in the measurement of fetal CRL on percentiles of EFW at 20, 32 and 36 weeks' gestation and classification as small-, large- or appropriate-for-gestational age. Published data on CRL measurement error were used to determine variation present in practice.

RESULTS

A measurement error of -2 mm in first-trimester CRL shifts an EFW on the 10^th percentile at the 20-week scan to around the 20^th percentile, and the effect of a CRL measurement error of + 2 mm would shift an EFW on the 10^th percentile to around the 5^th percentile. At 32 weeks, a first-trimester CRL measurement error would shift an EFW on the 10^th percentile to the 7^th (+ 2 mm) or 14^th (-2 mm) percentile; at 36 weeks, the EFW would shift from the 10^th percentile to the 8^th (+ 2 mm) or 12^th (-2 mm) percentile. Published data suggest that measurement errors of 2 mm or more are common in practice.

CONCLUSION

Because of the widespread and potentially severe consequences of CRL measurement errors as small as 2 mm on clinical assessment, patient management and research results, there is a need to increase awareness of the impact of CRL measurement error and to reduce measurement error variation through standardization and quality control. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Antidepressant use in pregnancy and severe cardiac malformations: Danish register-based study

OBJECTIVE

Studies restricted to live births may underestimate severe teratogenic effects. We address the limitation by including data from both prenatal and postnatal diagnoses of cardiac malformations.

DESIGN

Register-based study.

SETTING

Denmark.

POPULATION

364 012 singleton pregnancies from 2007 to 2014.

METHODS

We used data from five nationwide registries. Exposure to antidepressants was measured using redeemed prescriptions.

MAIN OUTCOME MEASURES

Pregnancies with cardiac malformations that end in miscarriage, termination, stillbirth, postnatal death or cardiac surgery <1 year of birth were classified as severe cardiac malformations (SCM). Propensity scores with adjusted prevalence ratios (PRs) were calculated.

RESULTS

SCM were reported in 972 of 364 012 pregnancies overall and in 16 of 4105 exposed. For venlafaxine, the PR for SCM was 2.13 (95% confidence interval [CI] 0.89-5.13), 1.73 (95% CI 1.08-2.77) for other cardiac malformations, and there was a cluster of hypoplastic left heart syndromes (HLHS) (crude PR 17.4 [95% CI 6.41-47.2]), none of which ended in a live birth. For HLHS, the absolute risk increase was 4.4/1000 and the number needed to harm was 225. For selective serotonin reuptake inhibitors, the PRs were 1.09 (95% CI 0.52-2.30) and 1.38 (95% CI 1.00-1.92) for SCM and other cardiac malformations, respectively.

CONCLUSIONS

Pregnancy exposure to venlafaxine is associated with an increased risk of severe cardiac malformations but with a low absolute risk. Potential mechanisms include direct effects or confounding by indication. Venlafaxine exposure is a marker for risk pregnancies for which fetal echocardiography may be considered.

TWEETABLE ABSTRACT

Exposure to venlafaxine is associated with an increased risk of cardiac malformations but with a low absolute risk. TWEETABLE ABSTRACT.

National data on the early clinical use of non-invasive prenatal testing in public and private healthcare in Denmark 2013-2017

INTRODUCTION

In Denmark, non-invasive prenatal testing (NIPT) has been used since 2013. We aimed to evaluate the early clinical use of NIPT in Danish public and private healthcare settings before NIPT became an integrated part of the national guidelines on prenatal screening and diagnosis in 2017.

MATERIAL AND METHODS

NIPT data were collected between March 2013 and June 2017 from national public registries and private providers. Results from follow-up samples (chorionic villi, amniotic fluid, postnatal blood or fetal tissue) were included from The Danish Cytogenetics Central Registry and indications and outcome from The Danish Fetal Medicine Database.

RESULTS

A total of 3936 NIPT results were included in the study from public hospitals (n = 3463, 88.0%) and private clinics (n = 473, 12.0%). The total number of prenatal tests was 19 713 during the study period: 20% were NIPT analyses (n = 3936) and 80% invasive procedures (n = 15 777). Twenty-five percent of NIPTs in the private clinics were performed before gestational week 11⁺⁰ , whereas NIPT in public settings was used only after combined first trimester screening (P < .001). Regardless of indication, the national public sensitivity was 96.9% (95% CI 82.0%-99.8%) for trisomy 21, 100% (95% CI 46.3%-100%) for trisomy 18, 100% (95% CI 5.5%-100%) for trisomy 13, and 87.0% (95% CI 74.5%-92.4%) for any fetal chromosomal aberration. Forty-seven true-positive NIPT results included cases of common aneuplodies (trisomy 21, n = 31; trisomy 18, n = 5; and trisomy 13, n = 1), sex chromosomal aberrations (n = 7) and atypical chromosomal aberrations (n = 3). One false-negative NIPT result occurred (trisomy 21). Of 47 cases, 21 (45%) cases with a true-positive NIPT result resulted in live births by choice; 11 of these children had Down and 4 had Edwards syndrome.

CONCLUSIONS

The total number of NIPT analyses was low compared with the number of invasive procedures in the implementation period. In contrast to the generally high termination rate after a positive result following invasive testing in Denmark, a high proportion of true-positive NIPT results from the public setting resulted in live births. NIPT may be an important risk-free alternative to invasive testing for a minority of women in the public setting who wish to use prenatal genetic testing for information only and not for reproductive decision-making.

Associations Between ADHD Medication Use in Pregnancy and Severe Malformations Based on Prenatal and Postnatal Diagnoses: A Danish Registry-Based Study

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) medications are increasingly used in pregnancy. Studies on the pregnancy safety of these medications that are restricted to live births may underestimate severe teratogenic effects that cause fetal demise or termination of pregnancy. The present study addresses this limitation by including data from both prenatal and postnatal diagnoses of major malformations.

METHODS

A nationwide registry-based study was conducted of 364,012 singleton pregnancies in Denmark from November 1, 2007, to February 1, 2014. Exposures to ADHD medication were obtained from redeemed prescriptions from the Danish Health Services Prescription Database. Outcome data included prenatally diagnosed malformations from the Danish Fetal Medicine Database and postnatally diagnosed malformations from the Danish National Patient Registry. The primary outcome was major malformations overall, and secondary outcomes were malformations of the central nervous system and cardiac malformations. The comparison group was pregnancies with no redeemed prescriptions for ADHD medication. We defined severe cardiac malformations (SCM) as concurrent diagnoses of a cardiac malformation with miscarriage, termination, stillbirth, postnatal death, or cardiac surgery within 1 year of birth.

RESULTS

The prevalence of first-trimester exposure to ADHD medication increased during the study period from 0.05% in 2008 to 0.27% in 2013, with the majority (473/569) of the exposures being to methylphenidate. There were 5.1% malformations overall and 2.1% cardiac malformations among the exposed compared to 4.6% and 1.0%, respectively, among the unexposed. For methylphenidate, the adjusted prevalence ratios (PRs) were 1.04 (95% confidence interval [CI], 0.70-1.55) for malformations overall and 1.65 (95% CI, 0.89-3.05) for any cardiac malformations (number needed to harm [NNH] = 92), with septum defects in 10 out of 12 cases. The PR for ventricular septal defect was 2.74 (95% CI, 1.03-7.28) and for SCM, 2.59 (95% CI, 0.98-6.90).

CONCLUSIONS

Exposure to methylphenidate was not associated with an increased risk of malformations overall in data that included information from both prenatal and postnatal diagnoses of major malformations. There was an increased risk of cardiac malformations with NNH of 92 based on 12 cases among the exposed. More data are needed on other types of ADHD medication.

Nuchal translucency of 3.0-3.4 mm an indication for NIPT or microarray? Cohort analysis and literature review

Introduction

Currently fetal nuchal translucency (NT) ≥3.5 mm is an indication for invasive testing often followed by chromosomal microarray. The aim of this study was to assess the risks for chromosomal aberrations in fetuses with an NT 3.0‐3.4 mm, to determine whether invasive prenatal testing would be relevant in these cases and to assess the residual risks in fetuses with normal non‐invasive prenatal test (NIPT) results.

Material and methods

A retrospective study and meta‐analysis of literature cases with NT between 3.0 and 3.4 mm and 2 cohorts of pregnant women referred for invasive testing and chromosomal microarray was performed: Rotterdam region (with a risk >1:200 and NT between 3.0 and 3.4 mm) tested in the period July 2012 to June 2019 and Central Denmark region (with a risk >1:300 and NT between 3.0 and 3.4 mm) tested between September 2015 and December 2018.

Results

A total of 522 fetuses were referred for invasive testing and chromosomal microarray. Meta‐analysis indicated that in 1:7.4 (13.5% [95% CI 8.2%‐21.5%]) fetuses a chromosomal aberration was diagnosed. Of these aberrant cases, 47/68 (69%) involved trisomy 21, 18, and 13 and would potentially be detected by all NIPT approaches. The residual risk for missing a (sub)microscopic chromosome aberration depends on the NIPT approach and is highest if NIPT was performed only for common trisomies–1:21 (4.8% [95% CI 3.2%‐7.3%]). However, it may be substantially lowered if a genome‐wide 10‐Mb resolution NIPT test was offered (~1:464).

Conclusions

Based on these data, we suggest that the NT cut‐off for invasive testing could be 3.0 mm (instead of 3.5 mm) because of the high risk of 1:7.4 for a chromosomal aberration. If women were offered NIPT first, there would be a significant diagnostic delay because all abnormal NIPT results need to be confirmed by diagnostic testing. If the woman had already received a normal NIPT result, the residual risk of 1:21 to 1:464 for chromosome aberrations other than common trisomies, dependent on the NIPT approach, should be raised. If a pregnant woman declines invasive testing, but still wants a test with a broader coverage of clinically significant conditions then the genome‐wide >10‐Mb resolution NIPT test, which detects most aberrations, could be proposed.

Current use of noninvasive prenatal testing in Europe, Australia and the USA: A graphical presentation

INTRODUCTION

Noninvasive prenatal testing (NIPT) using cell-free fetal DNA has increasingly been adopted as a screening tool for fetal aneuploidies. Several studies have discussed benefits and limitations of NIPT compared with both ultrasound and invasive procedures, but in spite of some shortcomings NIPT has become extensively used within the last 5 years. This study aims to describe the current use of NIPT in Europe, Australia and the USA.

MATERIAL AND METHODS

We conducted a survey to describe the current use of NIPT. Colleagues filled in a simple email-based questionnaire on NIPT in their own country, providing information on (a) access to NIPT, (b) NIPT's chromosomal coverage, (c) financial coverage of NIPT for the patient and (d) the proportion of women using NIPT in pregnancy. Some data are best clinical estimates, due to a lack of national data.

RESULTS

In Europe, 14 countries have adopted NIPT into a national policy/program. Two countries (Belgium and the Netherlands) offer NIPT for all pregnant women, whereas most other European countries have implemented NIPT as an offer for higher risk women after first trimester screening. In Australia, either combined first trimester screening (cFTS) or NIPT is used as a primary prenatal screening test. In the USA, there are no national consensus policies on the use of NIPT; however, NIPT is widely implemented. In most European countries offering NIPT, the proportion of women using NIPT is well below 25%. In the Netherlands, Austria, Italy, Spain and most Australian and American States, 25%-50% of women have NIPT performed and in Belgium testing is above 75%. In most countries, NIPT reports on trisomy 13, 18 and 21, and often also on sex chromosome aneuploidies. Only in Belgium, the Netherlands, Lithuania, Greece, Cyprus and Italy is NIPT offered predominantly as a genome-wide test (including some microdeletions or a whole genome coverage).

CONCLUSIONS

Noninvasive prenatal testing has been widely adopted throughout Europe, Australia and the USA, but only a few countries/states have a national policy on the use of NIPT. The variation in NIPT utilization is considerable.

Prevalence of mosaicism in uncultured chorionic villus samples after chromosomal microarray and clinical outcome in pregnancies affected by confined placental mosaicism

OBJECTIVE

To evaluate the prevalence of mosaicism in chorionic villus sampling (CVS) samples after chromosomal microarray (CMA) and clinical outcome of pregnancies affected by confined placental mosaicism.

METHOD

We retrieved all results from CMA, array-based comparative genomic hybridization, on CVS samples from January 2011 to November 2017 from Central and North Denmark Regions. Mosaic results from uncultured chorionic villi, cytotrophoblasts and mesenchymal cells, after CVS and follow-up on amniocytes, fetal tissue, or postnatal blood were studied and matched with clinical data from The Danish Fetal Medicine Database.

RESULTS

Prevalence of mosaicism was 93 out of 2,288 (4.1%) CVS samples of which 17 (18.3%) concerned submicroscopic copy number variations (CNVs) <10 Mb. Follow-up analyses were performed in 62 cases. True fetal mosaicism (TFM) was confirmed in 18.4% (7/38) when mosaicism involved whole chromosome aneuploidy and in 25.0% (6/24), when involving a CNV (P = .59). Median birth weight z-score was higher in cases of confined placental mosaicism for a CNV (0.21) than cases involving whole chromosomes (-0.74) (P = .02).

CONCLUSION

Prevalence of mosaicism in CVS samples is higher after CMA on uncultured tissue than after conventional karyotyping on cultured tissue. The risk of TFM is equally high in cases of mosaicism for CNVs and whole chromosomes.

Neurodevelopmental disorder in children believed to have isolated mild ventriculomegaly prenatally

OBJECTIVE

To estimate the prevalence of specific neurodevelopmental disorders in children believed to have isolated mild ventriculomegaly (IMV) prenatally in the second trimester of pregnancy, in order to optimize the counseling process.

METHODS

This was a nationwide registry-based study including all singleton pregnancies that had first- and second-trimester ultrasound scans in the period 1^st January 2008 to 1^st October 2014, identified in the Danish Fetal Medicine Database and local clinical databases in Denmark. All fetuses diagnosed prenatally with IMV (measurement of the atrium of the lateral ventricles, 10.0-15.0 mm) between 18 and 22 weeks' gestation were followed up in national patient registers until the age of 2-7 years. Information was obtained on the diagnoses of intellectual disability, cerebral palsy, autism spectrum disorder, epilepsy and impaired psychomotor development. Neurodevelopmental disorders were compared between those with postnatally confirmed IMV and a reference population of children in the same age range.

RESULTS

Of a cohort of 292 046 fetuses, 133 were found to have apparent IMV on the second-trimester scan for fetal malformations. In 11 cases, long-term follow-up was not possible owing to termination of pregnancy, spontaneous miscarriage, neonatal death or loss to follow-up. Of the 122 liveborn children followed up until 2-7 years, 15 were identified as having an additional abnormality while 107 were confirmed postnatally to have IMV. Of these 107 children, the diagnosis of a neurodevelopmental disorder was registered in six (5.6%), corresponding to an odds ratio of 2.64 (95% CI, 1.16-6.02), as compared with the reference population. The diagnoses were autism spectrum disorder, epilepsy and impaired psychomotor development. None of these 107 children was diagnosed with intellectual disability or cerebral palsy.

CONCLUSIONS

Our results show that a confirmed diagnosis of IMV was associated with an increased risk of a neurodevelopmental disorder, as compared with the reference population, but the absolute risk was low and there were no cases of intellectual disability or cerebral palsy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Outcomes of monoamniotic twin pregnancies managed primarily in outpatient care-a Danish multicenter study

INTRODUCTION

Monoamniotic twin pregnancies are high-risk pregnancies, and management by inpatient or frequent outpatient care is recommended. We report the outcomes of a national cohort of monoamniotic twin pregnancies managed primarily as outpatients.

MATERIAL AND METHODS

We prospectively analyzed the recorded data from the Danish Fetal Medicine Database, local databases, and medical records of all monoamniotic twin pregnancies diagnosed at the first trimester scan or later, and managed at the six major fetal medicine centers in Denmark over a 10-year period.

RESULTS

Sixty-one monoamniotic twin pregnancies were included. Thirteen pregnancies were terminated early. Of the remaining 48 pregnancies with a normal first trimester scan, there were 36 fetal losses (25 spontaneous miscarriages <22⁺⁰  weeks, 3 late terminations and 8 intrauterine deaths >22 weeks) and 60 liveborn children (62.5%), all of whom were delivered by cesarean delivery at a median gestational age of 33⁺⁰  weeks. Three children had minor malformations and there was 1 pregnancy with twin-to-twin transfusion syndrome. After 26⁺⁰  weeks, 78.8% were managed as outpatients. Intrauterine death occurred in 3.8% of outpatients and in 28.6% of inpatients (admitted due to complications). At weeks 32, 33 and 34, the prospective risk of intrauterine death was 6.9%, 4.2% and 5.9%, respectively.

CONCLUSION

In this nationwide, unselected population, only 62.5% of fetuses with a normal first trimester scan were born alive. In contrast, the mortality was 3.8% after 26 weeks among the 78.8% of the cohort that was managed as outpatients. More knowledge is still needed to predict which pregnancies are at the highest risk of intrauterine death.

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.

Tinzaparin for the treatment of foetal growth retardation: An open-labelled randomized clinical trial

OBJECTIVE

Foetal growth retardation (FGR) is a leading cause of perinatal death and long-term harms at survivors. Placental infarction plays a role in FGR, yet, no trials have evaluated whether low molecular weight heparins increase birth weight in ongoing FGR pregnancies.

METHODS

An open-labelled randomized trial in Denmark during 2011-2016, including singleton pregnant women with FGR (estimated foetal weight < 2.3 percentile) diagnosed before gestational weeks 32. Participants were randomly assigned using sealed, blinded envelopes 1:1 to tinzaparin (4500 IU daily until 37 gestational weeks) or no tinzaparin. The primary outcomes were the observed birthweight relative to the expected for gestational age and gender, and foetal growth rates in the two trial groups evaluated by an intention to treat analysis.

RESULTS

We enrolled 53 women. The mean gestational age was 261 days in the tinzaparin group and 246 days in the no treatment group. The mean birth weight was 2229 g in the tinzaparin group compared to 1968 g in the no treatment group. However, the birth weight relative to the expected from gestational age and gender was only 2.5 percentage points higher in the tinzaparin group [-5.1 to 10.0] (p = 0.51). The foetal growth rate during follow-up was 124 g/week in the tinzaparin group and 119 g/week in the no treatment group, a difference of 5 g/week [-19 to 29] (p = 0.67). Two perinatal deaths both occurred in the no treatment group.

CONCLUSION

We found no evidence of a tinzaparin effect on the foetal growth rate or the birth weight after adjustment for gestational age.

Targeted gene sequencing and whole-exome sequencing in autopsied fetuses with prenatally diagnosed kidney anomalies

Identification of fetal kidney anomalies invites questions about underlying causes and recurrence risk in future pregnancies. We therefore investigated the diagnostic yield of next-generation sequencing in fetuses with bilateral kidney anomalies and the correlation between disrupted genes and fetal phenotypes. Fetuses with bilateral kidney anomalies were screened using an in-house-designed kidney-gene panel. In families where candidate variants were not identified, whole-exome sequencing was performed. Genes uncovered by this analysis were added to our kidney panel. We identified likely deleterious variants in 11 of 56 (20%) families. The kidney-gene analysis revealed likely deleterious variants in known kidney developmental genes in 6 fetuses and TMEM67 variants in 2 unrelated fetuses. Kidney histology was similar in the latter 2 fetuses-presenting a distinct prenatal form of nephronophthisis. Exome sequencing identified ROBO1 variants in one family and a GREB1L variant in another family. GREB1L and ROBO1 were added to our kidney-gene panel and additional variants were identified. Next-generation sequencing substantially contributes to identifying causes of fetal kidney anomalies. Genetic causes may be supported by histological examination of the kidneys. This is the first time that SLIT-ROBO signaling is implicated in human bilateral kidney agenesis.

Chromosomal microarray as primary diagnostic genomic tool for pregnancies at increased risk within a population-based combined first-trimester screening program

OBJECTIVE

To evaluate the performance of high-resolution chromosomal microarray (CMA) as the standard diagnostic approach for genomic imbalances in pregnancies with increased risk based on combined first-trimester screening (cFTS).

METHODS

This was a retrospective study of genomic findings in a cohort of 575 consecutive pregnancies undergoing invasive testing because of a cFTS risk ≥ 1:300 on a publicly funded population-based screening program in the Central and Northern Regions of Denmark, between September 2015 and September 2016. Women with fetal nuchal translucency thickness ≥ 3.5 mm or opting for non-invasive prenatal testing (NIPT) were excluded. Comparative genomic hybridization was performed using a 180-K oligonucleotide array on DNA extracted directly from chorionic villus/amniocentesis samples. Genomic outcomes were reported in relation to cFTS findings.

RESULTS

Of the 575 pregnancies that underwent invasive testing, CMA detected 22 (3.8% (95% CI, 2.5-5.7%)) cases of trisomies 21, 18 and 13, 14 (2.4% (95% CI, 1.4-4.0%)) cases of other types of aneuploidy and 15 (2.6% (95% CI, 1.5-4.3%)) cases with a pathogenic or probably pathogenic copy number variant (CNV). Of the 15 CNVs, three were > 10 Mb and would probably have been detected by chromosomal analysis, but the other 12 would most probably not have been detected using conventional cytogenetic techniques; therefore, the overall detection rate of CMA (8.9% (95% CI, 6.8-11.5%)) was significantly higher than that estimated for conventional cytogenetic analysis (6.8% (95% CI, 5.0-9.1%)) (P = 0.0049). Reducing the cFTS risk threshold for invasive diagnostic testing to 1 in 100 or 1 in 50 would have led, respectively, to 60% or 100% of the pathogenic CNVs being missed.

CONCLUSIONS

CMA is a valuable diagnostic technique that can identify an increased number of genomic aberrations in pregnancies at increased risk on cFTS. Limiting diagnostic testing to pregnancies with a risk above 1 in 100 or 1 in 50, as proposed in contingent NIPT/invasive testing models, would lead to a significant proportion of pathogenic CNVs being missed at first-trimester screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Infants with prenatally diagnosed kidney anomalies have an increased risk of urinary tract infections

AIM

This study estimated the urinary tract infection (UTI) risk in a nationwide cohort of infants prenatally diagnosed with parenchymal kidney anomalies compared with a comparison cohort.

METHODS

A Danish population-based nationwide cohort of foetuses diagnosed with parenchymal kidney anomalies between 2007 and 2012 had previously been identified. These were compared with foetuses without kidney anomalies who were prenatally scanned the same year. Live born infants were followed from birth until the diagnosis of UTI, emigration, death or two years of age. Cumulative incidences of UTIs were computed. Mortality was estimated using the Kaplan-Meier method.

RESULTS

We identified 412 foetuses with parenchymal kidney anomalies out of 362 069 who underwent ultrasound scans and 277 were born alive. The overall risk of a UTI before the age of two years was 19%, and it was 14% among infants without prenatally diagnosed co-occurring urinary tract malformations. The corresponding risk in the 4074 controls was 1%. After two years, mortality was 2.2% in infants with prenatally diagnosed parenchymal kidney anomalies and 0.2% in the controls.

CONCLUSION

Infants prenatally diagnosed with parenchymal kidney anomalies had a substantially increased risk of UTI. Awareness of this increased risk may facilitate earlier diagnosis of UTIs in this population.

Experiences and expectations in the first trimester of pregnancy: a qualitative study

Background

A dominant context for pregnant women in the Western world is medical technologies such as ultrasound and screening. It has been argued that such technologies may result in tentative pregnancies, which may be particularly prominent in the first trimester. However, little is known about how women experience early pregnancy.

Objective

To explore the everyday experiences and expectations of first trimester pregnant women in a medicalized context of comprehensive and routine prenatal screening.

Design

Qualitative, semi‐structured interviews analysed using thematic analysis.

Setting

Between May 2015 and January 2016, participants were recruited from two general practices and one obstetric ultrasound unit in Aarhus, Denmark.

Participants

Twenty, first trimester pregnant women (15 primiparae, five multiparae) aged 21‐39 years.

Results

Early pregnancy is often kept secret in the first trimester due to a higher risk of miscarriage. However, the pregnancy is very real in the lives of the pregnant women who make it meaningful through practices of information seeking, listening to the body and anticipating the different milestones in pregnancy. First trimester screening represents one such milestone that is expected to mark a new and more certain phase in the pregnancy. A majority expects to terminate following a prenatal diagnosis, but this does not seem to influence their engagement with the pregnancy.

Conclusions

The pregnant women use medical technologies to mark a milestone in pregnancy but do not expect all concerns to disappear upon a normal screening result. The majority of women acknowledge that pregnancy involves simultaneous feelings of happiness and worry.

Increased nuchal translucency thickness and risk of neurodevelopmental disorders

OBJECTIVE

To investigate the association between fetal nuchal translucency (NT) thickness and neurodevelopmental disorders in euploid children.

METHODS

This study included 222 505 euploid children who had undergone routine first-trimester screening during fetal life. Children were divided according to prenatal NT into three groups: NT < 95^th percentile (n = 217 103 (97.6%)); NT 95^th -99^th percentile (n = 4760 (2.1%)); and NT > 99^th percentile (n = 642 (0.3%)). All children were followed-up to a mean age of 4.4 years. Information on diagnoses of intellectual disability, autism spectrum disorders (ASD), cerebral palsy, epilepsy and febrile seizures was obtained from national patient registries.

RESULTS

There was no excess risk of neurodevelopmental disorders among euploid children with first-trimester NT 95^th -99^th percentile. For children with NT > 99^th percentile, there were increased risks of intellectual disability (odds ratio (OR), 6.16 (95% CI, 1.51-25.0), 0.31%) and ASD (OR, 2.48 (95% CI, 1.02-5.99), 0.78%) compared with children with NT < 95^th percentile (incidence of 0.05% for intellectual disability and 0.32% for ASD), however, there was no detected increase in the risk of cerebral palsy (OR, 1.91 (95% CI, 0.61-5.95), 0.47%), epilepsy (OR, 1.51 (95% CI, 0.63-3.66), 0.78%) or febrile seizures (OR, 0.72 (95% CI, 0.44-1.16), 2.65%).

CONCLUSIONS

In a large unselected cohort of euploid children, there was no increased risk of neurodevelopmental disorders among those with a first-trimester NT 95^th -99^th percentile. Among euploid children with first-trimester NT > 99^th percentile, there were increased risks of intellectual disability and ASD, but the absolute risk was reassuringly low (< 1%). Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Coping with worry while waiting for diagnostic results: a qualitative study of the experiences of pregnant couples following a high-risk prenatal screening result

BACKGROUND

It is well documented that pregnant women experience increased worry and uncertainty following a high-risk prenatal screening result. While waiting for diagnostic results this worry continues to linger. It has been suggested that high-risk women put the pregnancy mentally 'on hold' during this period, however, not enough is known about how high-risk women and their partners cope while waiting for diagnostic results. The aim of this study was to identify the strategies employed to cope with worry and uncertainty.

METHODS

Qualitative, semi-structured interviews with 16 high-risk couples who underwent diagnostic testing. The couples were recruited at a university hospital fetal medicine unit in Denmark. Data were analysed using thematic analysis.

RESULTS

All couples reported feeling worried and sad upon receiving a high-risk screening result. While waiting for diagnostic results, the couples focused on coming to their own understanding of the situation and employed both social withdrawal and social engagement as strategies to prevent worry from escalating. Additionally, couples used gratitude, reassuring reasoning and selective memory as means to maintain hopes for a good outcome. Discussions about what to do in case of an abnormal test result were notably absent in the accounts of waiting. This bracketing of the potential abnormal result allowed the couples to hold on to a 'normal' pregnancy and to employ an 'innocent-till-proven-guilty' approach to their worries about the fetus's health. None of the interviewed couples regretted having prenatal screening and all of them expected to have prenatal screening in a future pregnancy.

CONCLUSIONS

The couples in this study did not put the pregnancy mentally 'on hold'. Worry and uncertainty must be understood as managed through a diverse range of practical and emotional strategies that change and overlap in the process of waiting. Clinicians may support appropriate ways of coping with worry and waiting through empathetic and empowering clinical communication. In addition to providing adequate information and presenting options available, clinicians may support high-risk women/couples by encouraging them to seek their own personal understandings and management strategies as a way to gain some control in an uncertain situation.

Linkage between the Danish National Health Service Prescription Database, the Danish Fetal Medicine Database, and other Danish registries as a tool for the study of drug safety in pregnancy

A linked population-based database is being created in Denmark for research on drug safety during pregnancy. It combines information from the Danish National Health Service Prescription Database (with information on all prescriptions reimbursed in Denmark since 2004), the Danish Fetal Medicine Database, the Danish National Registry of Patients, and the Medical Birth Registry. The new linked database will provide validated information on malformations diagnosed both prenatally and postnatally. The cohort from 2008 to 2014 will comprise 589,000 pregnancies with information on 424,000 pregnancies resulting in live-born children, ∼420,000 pregnancies undergoing prenatal ultrasound scans, 65,000 miscarriages, and 92,000 terminations. It will be updated yearly with information on ∼80,000 pregnancies. The cohort will enable identification of drug exposures associated with severe malformations, not only based on malformations diagnosed after birth but also including those having led to termination of pregnancy or miscarriage. Such combined data will provide a unique source of information for research on the safety of medications used during pregnancy.

Mechanism of pancreatic and liver malformations in human fetuses with short-rib polydactyly syndrome

BACKGROUND

The short-rib polydactyly (SRP) syndromes are rare skeletal dysplasias caused by abnormalities in primary cilia, sometimes associated with visceral malformations.

METHODS

The pathogenesis of ductal plate malformation (DPM) varies in different syndromes and has not been investigated in SRP. We have studied liver development in five SRP fetuses and pancreatic development in one SRP fetus, with genetically confirmed mutations in cilia related genes, with and without DPMs, using the immunoperoxidase technique, and compared these to other syndromes with DPM.

RESULTS

Acetylated tubulin expression was abnormal in DPM in SRP, Meckel syndrome, and autosomal recessive polycystic kidney disease (ARPKD), confirming ciliary anomalies. SDF-1 was abnormally expressed in SRP and two of three cases of autosomal dominant polycystic kidney disease (ADPKD) but not ARPKD or Meckel. Increased density of quiescent hepatic stellate cells was seen in SRP, Meckel, one of three cases of ARPKD, and two of three cases of ADPKD with aberrant hepatocyte expression of keratin 19 in SRP and ADPKD. Immunophenotypic abnormalities were present even in fetal liver without fully developed DPMs. The SRP case with DPM and pancreatic malformations showed abnormalities in the pancreatic head (influenced by mesenchyme from the septum transversum, similar to liver) but not pancreatic body (influenced by mesenchyme adjacent to the notochord).

CONCLUSION

In SRP, there are differentiation defects of hepatocytes, cholangiocytes, and liver mesenchyme and, in rare cases, pancreatic mesenchymal anomalies. The morphological changes were subtle in early gestation but immunophenotypic abnormalities were present. Mesenchymal-epithelial interactions may contribute to the malformations. Birth Defects Research (Part A) 106:549-562, 2016. © 2016 Wiley Periodicals, Inc.

Risk of fetal loss associated with invasive testing following combined first-trimester screening for Down syndrome: a national cohort of 147,987 singleton pregnancies

OBJECTIVE

To assess prospectively the risk of fetal loss associated with chorionic villus sampling (CVS) and amniocentesis (AC) following combined first-trimester screening (cFTS) for Down syndrome.

METHODS

This was a nationwide population-based study (Danish Fetal Medicine Database, 2008-2010) including 147,987 women with singleton pregnancy who underwent cFTS. Propensity score stratification was used to assess the risk of fetal loss with and without invasive testing. Analyses were performed between 3 and 21 days after cFTS for CVS and between 28 and 42 days after cFTS for AC. Results are reported as average risk differences with 95% CIs.

RESULTS

The risks of miscarriage and stillbirth were not higher in women exposed to CVS or AC compared with unexposed women, independent of the analysis time-point. The average effect of CVS on risk of miscarriage was -0.08% (95% CI, -0.64; 0.47) at 3 days and -0.21% (95% CI, -0.58; 0.15) at 21 days after cFTS, while the effect on risk of stillbirth was -0.18% (95% CI, -0.50; 0.13) at 3 days and -0.27% (95% CI, -0.58; 0.04) at 21 days after cFTS. Regarding the effect of AC on risk of miscarriage, the analysis at 28 days after cFTS showed an average effect of 0.56% (95% CI, -0.21; 1.33), while the effect on risk of stillbirth was 0.09% (95% CI, -0.39; 0.58) at 42 days after cFTS.

CONCLUSION

Neither CVS nor AC was associated with increased risk of miscarriage or stillbirth. These findings indicate that the procedure-related risk of CVS and AC is very low.

Preferences for prenatal tests for Down syndrome: an international comparison of the views of pregnant women and health professionals

Non-invasive prenatal testing is increasingly available worldwide and stakeholder viewpoints are essential to guide implementation. Here we compare the preferences of women and health professionals from nine different countries towards attributes of non-invasive and invasive prenatal tests for Down syndrome. A discrete choice experiment was used to obtain participants' stated preference for prenatal tests that varied according to four attributes: accuracy, time of test, risk of miscarriage, and type of information. Pregnant women and health professionals were recruited from Canada, Denmark, Iceland, Israel, Italy, the Netherlands, Portugal, Singapore, and the United Kingdom. A total of 2666 women's and 1245 health professionals' questionnaires were included in the analysis. Differences in preferences were seen between women and health professionals within and between countries. Overall, women placed greater emphasis on test safety and comprehensive information than health professionals, who emphasised accuracy and early testing. Differences between women's and health professionals' preferences are marked between countries. Varied approaches to implementation and service delivery are therefore needed and individual countries should develop guidelines appropriate for their own social and screening contexts.

Antibody response to influenza A(H1N1)pdm09 in vaccinated, serologically infected and unaffected pregnant women and their newborns

OBJECTIVE

To evaluate the serological response in pregnant Danish women immunized during the 2009 pandemic by serologic infection or by vaccination with influenza A(H1N1) Pandemrix(®) and describe levels of passively acquired maternal antibody in their offspring.

DESIGN

Observational cohort study.

SETTING

Department of Obstetrics, Aarhus University Hospital, Skejby, Denmark, October to December 2009.

POPULATION

Pregnant women and their offspring

METHODS

Serological analysis of antibodies to influenza A(H1N1)pdm09 by hemagglutination inhibition assay in 197 women and their offspring. Blood samples were collected consecutively at delivery from the mother and the umbilical cord. In a subgroup of 124 of the 197 women, an additional blood sample from gestational weeks 9-12 was available for analysis.

MAIN OUTCOME MEASURES

Seroconversion, geometric mean titer, geometric mean-fold rise and protective antibodies.

RESULTS

33 of the 124 subgroup women (27%) seroconverted during pregnancy, 79% after vaccination and 17% after serologic infection (p < 0.001). The geometric mean titer after delivery in non-vaccinated, non-serologically infected women was 17.1 (95%CI 15.7-18.6). The geometric mean titer increased significantly after serologic infection with H1N1 [76.5 (95%CI 51.3-113.9), p < 0.001] and after vaccination [589.6 (95%CI 339.3-1024.7), p < 0.001]. The geometric mean-fold rise (mother at delivery/mother early pregnancy) was significantly higher after vaccination [2.23 (1.93-2.54)] than after serologic infection [1.73 (1.59-1.87), p = 0.013]. In newborns of vaccinated mothers, 89.5% had protective antibody levels compared with 15.8% in newborns of serologically infected mothers (p < 0.001).

CONCLUSIONS

Influenza vaccination during pregnancy confers passive immunity to the newborn.

Chromosomal microarray in fetuses with increased nuchal translucency

OBJECTIVE

To assess the clinical value of using high-resolution chromosomal microarray (CMA) for the examination of genomic imbalances in prenatal uncultured chorionic villus samples from fetuses with increased nuchal translucency (NT) and a normal quantitative fluorescent polymerase chain reaction (QF-PCR) result, in a clinical setting in which more than 95% of pregnant women receive first-trimester combined screening.

METHODS

From January 2013 to July 2014, we included 132 chorionic villus samples from consecutive ongoing pregnancies, with fetal NT ≥ 3.5  mm at 11-13 weeks' gestation, from obstetric units (publicly funded healthcare) in Central and North Denmark Regions. DNA was extracted directly from the samples and examined with QF-PCR (n = 132) and 180 kb oligonucleotide array-based comparative genomic hybridization (n =  94).

RESULTS

In 38 cases, aneuploidies for chromosomes 18, 21 or X, or triploidy, were detected by QF-PCR. Among the 94 cases with a normal QF-PCR result, we detected pathogenic copy number variants (CNVs) by CMA in 12 fetuses (12.8% (95% CI, 7.5-21.0%)). In an additional three (3.2%) cases, CNVs with uncertain clinical significance were detected.

CONCLUSION

CMA is a valuable diagnostic technique in pregnancies with isolated fetal NT ≥ 3.5 mm.

Does screening for Down's syndrome cause anxiety in pregnant women? A systematic review

BACKGROUND

Prenatal screening for Down's syndrome and other chromosomal abnormalities is included in prenatal care programs in many countries. However, the potential association between prenatal screening and maternal anxiety remains an issue of debate.

OBJECTIVE

To systematically review and summarize the current scientific evidence on whether screening for Down's syndrome might cause anxiety in pregnant women with a negative or a false-positive screening result.

METHODS

Five databases (PubMed, Embase, Cinahl, PsychInfo and Cochrane) were systematically searched for randomized controlled trials or cohort studies comparing screening and no screening, or comparing different types of screening for Down's syndrome. The search was limited to studies published between September 2001 and April 2013. In all, 316 studies were identified through search of databases and 40 were included for full-text assessment. Two observers independently screened the articles and seven studies satisfied the inclusion criteria. They were subsequently assessed for risk of bias and level of evidence.

MAIN OUTCOME MEASURES

Quantitative measurements of maternal anxiety or worry.

RESULTS

Two studies compared anxiety in pregnant women who accepted or declined screening and showed no difference between groups. All studies described a decrease in anxiety following a screen-negative result. Four studies reported that women's anxiety levels increased significantly upon receiving a screen-positive result. However, after a normal diagnostic result, anxiety levels declined to the same level as for screen-negative women.

CONCLUSION

Studies using quantitative, validated measures to estimate anxiety showed no association between screening and residual anxiety.

Outcome of fetuses with short femur length detected at second-trimester anomaly scan: a national survey

OBJECTIVE

To assess the relationship between the finding of fetal femur diaphysis length (FL) below the 5(th) percentile at the second-trimester scan and pregnancy outcome, in a population in which more than 90% of women attend first-trimester screening.

METHODS

This was a retrospective study of all Danish singleton pregnancies with a 17-22-week anomaly scan between 1 January 2008 and 30 June 2011. Information on FL and gestational age (GA) at anomaly scan, on birth weight and GA at delivery and on chromosomal abnormalities was obtained from the Danish Fetal Medicine Database.

RESULTS

Short FL was identified in 2718 (1.8%) of 147,766 fetuses and was present in 11 (16.2%) of the 68 fetuses affected by trisomy 21 (positive likelihood ratio (LR+) 8.8 (95% CI, 5.1-15.2)). Trisomy 13/18 and unbalanced autosomal structural abnormalities were also associated with a short FL in three (12.0%, LR+ 6.5 (95% CI, 2.3-18.9)) and eight (32.0%, LR+ 17.4 (95% CI, 9.8-30.9)) of the cases, respectively. The risk of a fetus having trisomy 21, trisomy 18, trisomy 13 or an unbalanced autosomal structural abnormality was 1 : 123 (95% CI, 79-192), given a short FL. Pregnancies with a fetus with short FL were more often affected by early preterm delivery (before 34 weeks) (5.6%; odds ratio (OR) = 4.2 (95% CI, 3.5-4.9)) and small-for-gestational-age (SGA) infants (13.9%; OR = 4.3 (95% CI, 3.8-4.8)).

CONCLUSION

Short FL at the second-trimester anomaly scan is associated with a significantly higher relative risk of chromosomal abnormalities, and a substantially higher absolute risk for SGA and early preterm delivery.

Potential diagnostic consequences of applying non-invasive prenatal testing: population-based study from a country with existing first-trimester screening

OBJECTIVES

Targeted non-invasive prenatal testing (NIPT) tests for trisomies 21, 18 and 13 and sex chromosome aneuploidies and could be an alternative to traditional karyotyping. The aim of this study was to determine the risk of missing other abnormal karyotypes of probable phenotypic significance by NIPT.

METHODS

This was a retrospective population-based analysis of all singleton pregnancies booked for combined first-trimester screening (cFTS) in Denmark over a 4-year period. Data concerning maternal demographics, cFTS and prenatal or postnatal karyotypes were collected from the Danish Fetal Medicine database. Karyotypes were classified according to whether the chromosomal anomaly would have been detected by NIPT and whether it was likely to affect phenotype.

RESULTS

cFTS was completed in 193638 pregnancies. 10205 (5.3%) had cytogenetic or molecular analysis performed. Of these, 1122 (11.0%) had an abnormal karyotype, of which 262 (23.4%) would have been missed by NIPT, but would probably have been clinically significant. The prevalence of such 'atypical abnormal karyotypes' was increased in women above 45 years of age, in pregnancies with increased nuchal translucency (NT) thickness (≥ 3.5 mm), with abnormal levels of free β-human chorionic gonadotropin (<0.2 or ≥ 5.0 multiples of the median (MoM)) or pregnancy-associated plasma protein-A<0.2 MoM. One or more of these factors was present in 3% of women, and the prevalence of atypical abnormal karyotypes in this high-risk cohort was 1.6%.

CONCLUSIONS

A significant proportion of karyotypic abnormalities will be missed by targeted NIPT. Women of advanced maternal age, or with increased fetal NT or abnormal biochemistry, have a higher risk of having a fetus affected by an atypical abnormal karyotype and need to be counseled accordingly when considering NIPT.

Prenatal diagnosis: array comparative genomic hybridization in fetuses with abnormal sonographic findings

OBJECTIVE

To evaluate the clinical value of a high-resolution whole-genome array method for examination of genomic imbalances in prenatal samples (46 amniotic fluid, 17 chorionic villus, and 26 products of conception) from fetuses with abnormal ultrasound, in a clinical setting where more than 90% of pregnant women receive first-trimester combined screening and a second-trimester anomaly scan.

DESIGN

Cross-sectional study.

SETTING

Fetal medicine units (national healthcare system) in Central and North Denmark Regions from March 2009 to April 2012.

SAMPLES

Eighty-nine samples obtained at 11.5-35.0 (mean 19.3) gestational weeks, either during ongoing pregnancy or after termination.

METHODS

DNA was extracted directly from amniotic fluid cells and chorionic villus samples, or from cultured cells, and examined with 80-kb resolution oligonucleotide array-based comparative genomic hybridization (aCGH).

MAIN OUTCOME MEASURES

Clinically significant copy number variations identified by aCGH.

RESULTS

We detected clinically significant copy number variations in 11 fetuses (12%, confidence interval 6.0-19%) with structural malformations. Three fetuses (3.4%) had uncertain clinical significant variations and incidental findings.

CONCLUSIONS

aCGH is a valuable diagnostic tool when fetal malformations are detected. More affected fetuses may be diagnosed at an earlier gestational age providing better possibilities for postnatal treatment and allowing for women to decide earlier on termination of pregnancy. When a normal result has reduced the risk of significant chromosomal aberration, aCGH may facilitate parental decision-making on whether to continue the pregnancy.

Temporal effects of maternal and pregnancy characteristics on serum pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin at 7-14 weeks' gestation

OBJECTIVE

The aim of this study was to investigate gestational age-dependent effects of racial origin, smoking status and mode of conception on maternal serum levels of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 7-14 weeks' gestation.

METHODS

This was an analysis of data from prospective first-trimester combined screening for aneuploidies in singleton pregnancies, with β-hCG and PAPP-A measured at 7 + 1 to 14 + 3 weeks' gestation. We included 27,908 pregnancies from three centers in the U.K. and 125,461 pregnancies from 22 centers in Denmark, all with known normal fetal karyotype or resulting in the birth of a phenotypically normal neonate. Multiple regression modelling of log10 -transformed marker concentrations was used to produce log10 multiple of the median (MoM) values for free β-hCG and PAPP-A and to examine pregnancy characteristics that have significant effects on marker concentrations.

RESULTS

Serum free β-hCG and PAPP-A concentrations were significantly affected by gestational age, maternal weight, racial origin, parity, smoking and mode of conception. There were significant gestational age-dependent effects attributed to Afro-Caribbean race, smoking and conception through in-vitro fertilization (IVF) on PAPP-A and free β-hCG levels. In women of Afro-Caribbean race there was a weekly increase in PAPP-A of 5.3% and in free β-hCG of 1.8%. In smokers there was a weekly decrease in PAPP-A of 2.4% and in free β-hCG of 1.6%. In cases of IVF conceptions there was a weekly increase in PAPP-A of 4.5% and in free β-hCG of 4.6%.

CONCLUSIONS

Serum free β-hCG and PAPP-A concentrations at 7-14 weeks' gestation are affected by several pregnancy characteristics. The effects of Afro-Caribbean race, smoking and IVF conception change with gestational age.

Prospective study evaluating performance of first-trimester combined screening for trisomy 21 using repeat sampling of maternal serum markers PAPP-A and free β-hCG

OBJECTIVE

To prospectively evaluate the performance of first-trimester combined screening for trisomy 21 using the biochemical markers pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (free β-hCG) obtained before and at the time of the nuchal translucency (NT) scan.

METHODS

Three fetal medicine departments in Denmark participated in the study. Screening for trisomy 21 was set up as a two-step approach with blood sampling performed before the NT scan (early sample) and again at the time of the NT scan (late sample). PAPP-A and free β-hCG were measured on both the early and late samples. Age-standardized detection and false-positive rates for different screening protocols were calculated.

RESULTS

We collected two blood samples in 27 pregnancies affected by trisomy 21 and in 3891 control pregnancies. The early samples were taken between gestational ages 8 + 0 and 13 + 6 weeks, and the late samples between 11 + 3 and 14 + 6 weeks. The median interval between the samples was 17 (range, 1-40) days. We found a significantly better estimated screening performance when using early sampling vs late sampling (P < 0.05). With a risk cut-off of 1 in 100, at the time of the risk assessment the estimated detection and false-positive rates when using the early sample were 91% (95% CI, 81-98%) and 1.6% (95% CI, 1.3-2.0%), respectively. For fixed false-positive rates the highest detection rates were achieved using both blood samples. When comparing early sampling vs double sampling there was no significant difference in screening performance.

CONCLUSION

In combined first-trimester screening for trisomy 21, use of early sampling with measurement of PAPP-A and free β-hCG before the time of the NT scan can optimize screening performance. Using maternal serum markers obtained both before and at the time of the NT scan has the potential to further improve performance, but larger studies are needed to confirm this potential.