Early Detection of Isolated Severe Congenital Heart Defects Is Associated with a Lower Threshold to Terminate the Pregnancy

INTRODUCTION

Early detection of isolated severe congenital heart defects (CHDs) allows extra time for chromosomal analysis and informed decision making, resulting in improved perinatal management and patient satisfaction. Therefore, the aim of this study was to assess the value of an additional first-trimester screening scan compared to only a second-trimester scan in fetuses diagnosed with isolated severe CHDs. Prenatal detection rate, time of prenatal diagnosis, and pregnancy outcome were evaluated in the Netherlands after implementation of a national screening program.

MATERIALS AND METHODS

We performed a retrospective geographical cohort study and included 264 pre- and postnatally diagnosed isolated severe CHD cases between January 1, 2007, and December 31, 2015, in the Amsterdam region. Severe CHD was defined as potentially life threatening if intervention within the first year of life was required. Two groups were defined: those with a first- and second-trimester anomaly scan (group 1) and those with a second-trimester anomaly scan only (group 2). A first-trimester scan was defined as a scan between 11 + 0 and 13 + 6 weeks of gestation.

RESULTS

Overall, the prenatal detection rate for isolated severe CHDs was 65%; 63% were detected before 24 weeks of gestation (97% of all prenatally detected CHDs). Prenatal detection rate was 70.2% in the group with a first- and second-trimester scan (group 1) and 58% in the group with a second-trimester scan only (group 2) (p < 0.05). Median gestational age at detection was 19 + 6 (interquartile range [IQR] 15 + 4 - 20 + 5) in group 1 versus 20 + 3 (IQR: 20 + 0 - 21 + 1) in group 2 (p < 0.001). In group 1, 22% were diagnosed before 18 weeks of gestation. Termination of pregnancy rate in group 1 and group 2 were 48% and 27%, respectively (p < 0.01). Median gestational age at termination did not differ between the two groups.

CONCLUSION

Prenatal detection rate of isolated severe CHDs and termination of pregnancy rate was higher in the group with both a first- and second-trimester scan. We found no differences between timing of terminations. The additional time after diagnosis allows for additional genetic testing and optimal counseling of expectant parents regarding prognosis and perinatal management, so that well-informed decisions can be made.

Early Detection of Structural Anomalies in a Primary Care Setting in the Netherlands

OBJECTIVE

This study assessed the percentage and type of congenital anomalies diagnosed at first-trimester ultrasound (US) scan in a primary care setting without following a standardized protocol for fetal anatomical assessment.

MATERIALS AND METHODS

US scans performed between 11+0 and 13+6 weeks of gestation in pregnancies with estimated date of delivery between January 1, 2012 and January 1, 2016 were searched. Data were supplemented with results of 20-week scans and pregnancy outcome.

RESULTS

Of all scans, 38.6% were dating scans and 61.4% were part of first-trimester screening. Anomalies were diagnosed prenatally in 200 (1.8%) fetuses; 81 (0.7%) were chromosomal and 119 (1.1%) were structural. Of all prenatally detected anomalies, 27% (n = 32) were detected at first-trimester scan, with a false-positive rate of 0.04%. All cases of anencephaly (n = 4), encephalocele (n = 2), exomphalos (n = 9), megacystis (n = 4), and limb reduction (n = 1) were diagnosed. First-trimester detection of gastroschisis and congenital heart defects was 67 and 19%, respectively.

CONCLUSION

In a primary care setting, global fetal anatomical assessment at first-trimester scan without following a standardized protocol detects about 30% of all structural anomalies and most of the severe anomalies, with an extremely low false-positive rate. We hypothesize that additional training and use of a systematic protocol would improve early detection of structural anomalies.

Prevalence, diagnosis and outcome of cleft lip with or without cleft palate in The Netherlands

OBJECTIVE

To examine the accuracy and timing of diagnosis of fetal cleft lip with or without cleft palate (CL ± P) in the years following the introduction of a national screening program, and to assess the completeness and accuracy of information in The Netherlands Perinatal Registry.

METHODS

A list was obtained of cases with a prenatal or postnatal diagnosis of CL ± P from two fetal medicine units between 2008 and 2012. All cases of CL ± P were included irrespective of the presence or absence of additional anomalies. Cases were included if the estimated date of delivery was between 1 January 2008 and 31 December 2012.

RESULTS

During the study period, 330 cases of CL ± P were identified, with a prevalence of 15 per 10 000 pregnancies. The number of cases that were detected before 24 weeks' gestation increased during the study period, while the rate of termination of pregnancy did not change significantly (P = 0.511). CL ± P was isolated in 217 (66%) cases and karyotype was abnormal in 69 (21%) cases. In 5% of the cases in which CL ± P seemed to be isolated during the 18-23-week anomaly scan, postnatal array comparative genomic hybridization (array-CGH) revealed an abnormal karyotype and 50% of these cases had major additional anomalies. Examination of data from The Netherlands Perinatal Registry demonstrated that in 37% of cases CL±P was not recorded in the pregnancy records.

CONCLUSION

CL ± P is increasingly being diagnosed prenatally, without a significant effect on the rate of pregnancy termination. Further improvement in the diagnostic accuracy may be achieved by advocating prenatal array-CGH to reduce the frequency of unexpected anomalies being diagnosed after birth. It is important that healthcare providers register accurately the presence or absence of anomalies in the birth records to ensure that, in the future, data from The Netherlands Perinatal Registry can be relied upon to monitor prevalence. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Timing of detection of anencephaly in The Netherlands

OBJECTIVE

The objective of this study is to assess the gestational age at detection and prevalence of anencephaly in the North of The Netherlands over a 5-year period.

METHODS

A case list of all cases of anencephaly from two fetal medicine units was compiled. Cases were included if the estimated due date was between 1 August 2008 and 31 July 2013.

RESULTS

Overall prevalence of anencephaly was 5.4 per 10.000 pregnancies (n = 110). The majority of cases (69%) was detected before 18 weeks' gestation. Factors determining successful early diagnosis were competence level of the sonographers, with a significantly higher detection rate when scans were performed by a sonographer licensed by the Fetal Medicine Foundation (FMF) for nuchal translucency measurement (p = 0.001), and gestational age at or beyond 11 weeks of gestation (p = 0.024).

CONCLUSION

Improving detection of anencephaly in the first trimester requires ultrasound screening at or after 11 weeks of gestation, performed by experienced sonographers trained in recognizing fetal anomalies. Sonographers should be instructed that the goal of the first trimester scan is not only to measure nuchal translucency thickness but also to exclude major anomalies.

Impact of introduction of mid-trimester scan on pregnancy outcome of open spina bifida in The Netherlands

OBJECTIVE

To examine the impact of introduction of the mid-trimester scan on pregnancy outcome in cases of open spina bifida in two regions of The Netherlands.

METHODS

This was a retrospective cohort study of 190 cases of open spina bifida diagnosed pre- or postnatally, with an estimated date of delivery between 2003 and 2011.

RESULTS

With implementation of the mid-trimester scan the percentage of cases of open spina bifida detected before the 24(th) week of pregnancy increased from 43% to 88%. The rise in prenatal detection rate was associated with a significant increase in the number of terminated pregnancies and a decrease in the rate of perinatal loss; the percentage of children born alive did not change significantly. In the subgroup that underwent a scan between 18 and 24 weeks of pregnancy, cranial signs were present in 94.4% of cases.

CONCLUSION

Introduction of the mid-trimester scan has led to an increase in early identification of pregnancies complicated by open spina bifida. Pregnancies previously destined to end in perinatal loss are now terminated whilst pregnancies with a relatively good prognosis are frequently continued; the number of children with open spina bifida who are born alive has not changed significantly. Our study confirms that prenatal diagnosis is usually triggered by visualization of a lemon-shaped skull or a banana-shaped cerebellum.

Relationship of isolated single umbilical artery to fetal growth, aneuploidy and perinatal mortality: systematic review and meta-analysis

OBJECTIVE

To review the available literature on outcome of pregnancy when an isolated single umbilical artery (iSUA) is diagnosed at the time of the mid-trimester anomaly scan.

METHODS

We searched MEDLINE (1948-2012), EMBASE (1980-2012) and the Cochrane Library (until 2012) for relevant citations reporting on outcome of pregnancy with iSUA seen on ultrasound. Data were extracted by two reviewers. Where appropriate, we pooled odds ratios (ORs) for the dichotomous outcome measures: small for gestational age (SGA), perinatal mortality and aneuploidy. For birth weight we determined the mean difference with 95% CI.

RESULTS

We identified three cohort studies and four case-control studies reporting on 928 pregnancies with iSUA. There was significant heterogeneity between cohort and case-control studies. Compared to fetuses with a three-vessel cord, fetuses with an iSUA were more likely to be SGA (OR 1.6 (95% CI, 0.97-2.6); n = 489) or suffer perinatal mortality (OR 2.0 (95% CI, 0.9-4.2); n = 686), although for neither of the outcomes was statistical significance reached. The difference in mean birth weight was 51 g (95% CI, -154.7 to 52.6 g): n = 407), but again this difference was not statistically significant. We found no evidence that fetuses with iSUA have an increased risk for aneuploidy.

CONCLUSION

In view of the non-significant association between iSUA and fetal growth and perinatal mortality, and in view of the heterogeneity in studies on aneuploidy, we feel that large-scale, prospective cohort studies are needed to reach definitive conclusions on the appropriate work-up in iSUA pregnancies. At present, targeted growth assessment after diagnosis of iSUA should not be routine practice.

[Ventriculomegaly at the gestational age of 20 weeks; research into its incidence and related abnormalities]

OBJECTIVE

To describe the incidence and the prognostic value of foetal ventriculomegaly identified between 18-23 weeks of gestational age in the northeastern part of the Netherlands during the 2002-2010 period.

DESIGN

Retrospective cohort study.

METHOD

From the database of the University Medical Centre Groningen in the Netherlands, we selected all cases of singleton pregnancies in which ventriculomegaly was diagnosed at 18-23 weeks of gestation.

RESULTS

In 2002, ventriculomegaly was diagnosed prenatally in 1:7000 foetuses; the incidence increased to 1:1750 in 2010. In 33 (51%) of 65 affected foetuses, an associated severe physical abnormality was detected, in 5 (8%) a subtle sonomarker (subtle ultrasound finding) and in 8 (12%), a chromosomal defect. In 47% of the pregnancies where ventriculomegaly was associated with other defects, the parents opted for termination of pregnancy. In the group with isolated mild ventriculomegaly (10-12 mm), termination was performed in 1 of 19 cases; and in the group with the greater ventricular width of 13-14 mm, this decision was made for 5 of the 8 pregnancies. All continued pregnancies of foetuses with isolated ventriculomegaly resulted in live births. Isolated ventriculomegaly was diagnosed relatively more frequently in male foetuses.

CONCLUSION

The introduction of ultrasound scans as part of standard prenatal care has resulted in an increased incidence of foetal ventriculomegaly. Important factors for predicting the outcome of the pregnancy are the degree of ventricular dilatation, the foetus' gender and the presence or absence of associated abnormalities. It is therefore important to use a standardised protocol for measuring ventricular width, record the biparietal diameter and foetal gender, perform a systematic physical examination and use karyotyping.

New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study

OBJECTIVES

Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on crown-rump length and biparietal diameter and, second, to derive reference curves for normal fetal growth based on biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference and femur length from 10 weeks of gestational age onwards.

METHODS

A total of 8313 pregnant women were included for analysis in this population-based prospective cohort study. All women had repeated ultrasound assessments to examine fetal growth.

RESULTS

Charts for ultrasound dating of pregnancy, based on crown-rump length and biparietal diameter, were derived. Internal validation with the actual date of delivery showed that ultrasound imaging provided reliable gestational age estimates. Up to 92% of deliveries took place within 37-42 weeks of gestation if gestational age was derived from ultrasound data, compared with 87% based on a reliable last menstrual period. The earlier the ultrasound assessment the more accurate the prediction of date of delivery. After 24 weeks of gestation a reliable last menstrual period provided better estimates of gestational age. Reference curves for normal fetal growth from 10 weeks of gestational age onwards were derived.

CONCLUSIONS

Charts for ultrasound dating of pregnancy and reference curves for fetal biometry are presented. The results indicate that, up to 24 weeks of pregnancy, dating by ultrasound examination provides a better prediction of the date of delivery than does last menstrual period. The earlier the ultrasound assessment in pregnancy, preferably between 10 and 12 weeks, the better the estimate of gestational age.

Ethnic differences in prenatal growth and the association with maternal and fetal characteristics

OBJECTIVES

The objectives of this study were to determine ethnic differences in prenatal growth and to examine their association with differences in maternal and fetal characteristics such as maternal height, weight, age, parity and fetal gender.

METHODS

A total of 1494 women from Rotterdam, The Netherlands, with a low-risk pregnancy who participated in a population-based cohort study, the Generation R Study, were offered three ultrasound examinations during pregnancy. Multilevel modeling was applied to determine ethnic differences in (estimated) fetal weight (including birth weight) and in the separate biometric variables that were used to calculate the estimated fetal weight (abdominal circumference, head circumference and femur length). Additionally the association of ethnic differences with maternal and fetal characteristics (i.e. maternal weight, height, age, parity and fetal gender) was studied.

RESULTS

Turkish, Cape Verdian, Surinamese-Creole and Surinamese-Hindustani women had on average smaller fetuses than the native Dutch women. The differences became more pronounced towards term. In the Turkish group the differences were no longer statistically significant when adjusted for maternal weight, height, age, parity and fetal gender. In the Cape Verdian, Surinamese-Creole and Surinamese-Hindustani groups the differences decreased after adjustment (31%, 16% and 39%, respectively).

CONCLUSIONS

This study shows that there are ethnic differences in fetal growth, which to a large extent may be attributed to differences in maternal weight, height, age and parity. For some ethnic groups, however, additional factors are involved, as differences remain significant after correction for fetal and maternal characteristics.

Sequential Pathways of Testing After First-Trimester Screening for Trisomy 21

OBJECTIVE

To evaluate the performance and use of second-trimester multiple-marker maternal serum screening for trisomy 21 by women who had previously undergone first-trimester combined screening (nuchal translucency, pregnancy-associated plasma protein A, and free beta-hCG), with disclosure of risk estimates.

METHODS

In a multicenter, first-trimester screening study sponsored by the National Institute of Child Health and Human Development, multiple-marker maternal serum screening with alpha-fetoprotein, unconjugated estriol, and total hCG was performed in 4,145 (7 with trisomy 21) of 7,392 (9 with trisomy 21) women who were first-trimester screen-negative and 180 (7 with trisomy 21) of 813 (52 with trisomy 21) who were first-trimester screen-positive. Second-trimester risks were calculated using multiples of the median and a standardized risk algorithm with a cutoff risk of 1:270.

RESULTS

Among the first-trimester screen-negative cohort, 6 of 7 (86%) trisomy 21 cases were detected by second-trimester multiple-marker maternal serum screening with a false-positive rate of 8.9%. Among the first-trimester screen-positive cohort, all 7 trisomy 21 cases were also detected in the second trimester, albeit with a 38.7% false-positive rate.

CONCLUSION

Our data demonstrate that a sequential screening program that provides patients with first-trimester results and offers the option for early invasive testing or additional serum screening in the second trimester can detect 98% of trisomy 21-affected pregnancies. However, such an approach will result in 17% of patients being considered at risk and, hence, potentially having an invasive test.

LEVEL OF EVIDENCE

II-2

First-trimester trisomy screening: nuchal translucency measurement training and quality assurance to correct and unify technique

OBJECTIVE

To describe the process of training for measuring nuchal translucency at five clinical centers in North America and to evaluate methods of quality assurance and feedback.

DESIGN

Throughout a period of 18 months, the performance of sonographers in measuring fetal nuchal translucency was monitored using qualitative and quantitative methods of review. After 12 months, different approaches (written and personal feedback) were used to inform sonographers of technical aspects that needed to or could be improved.

RESULTS

On initial qualitative review, discrepancies in judgment from different reviewers coincided with suboptimal magnification, failure to visualize the amniotic membrane and/or use of cross-shaped calipers. At subsequent global review, 13 (29%) images of nuchal translucency measurements were considered unacceptable. Quantitative assessment revealed that, during the first part of the study, the means from four sonographers were significantly smaller and the mean from the fifth sonographer was significantly larger than expected on the basis of findings from The Fetal Medicine Foundation (P < 0.0001). Following feedback, sonographers who underestimated nuchal translucency and who received a written report only did not change measurements overall (P = 0.9759). In contrast, those who received additional intervention showed a marked difference (P < 0.0001).

CONCLUSIONS

Global qualitative review of images from one sonographer may be preferable to assessment of individual aspects of images. Results from global qualitative review correspond well with findings from quantitative analysis, indicating that the latter can be applied for ongoing audit. Observation of divergent results should prompt extensive personal feedback, rather than a written report, to prevent sonographers from settling in their own, inappropriate technique.