Screening for fetal anomalies by ultrasound at 14 and 21 weeks

Strategies for obstetricians and gynecologists to advance reproductive autonomy in a post-Roe landscape

The monumental reversal of Roe vs Wade dramatically impacted the landscape of reproductive healthcare access in the United States. The decision most significantly affects communities that historically have been and continue to be marginalized by systemic racism, classism, and ableism within the medical system. To minimize the harm of restrictive policies that have proliferated since the Supreme Court overturned Roe, it is incumbent on obstetrician-gynecologists to modify practice patterns to meet the pressing reproductive health needs of their patients and communities. Change will require cross-discipline advocacy focused on advancing equity and supporting the framework of reproductive justice. Now, more than ever, obstetrician-gynecologists have a critical responsibility to implement new approaches to service delivery and education that will expand access to evidence-based, respectful, and person-centered family planning and early pregnancy care regardless of their practice location or subspecialty.

The role of routine first-trimester ultrasound screening for central nervous system abnormalities: a longitudinal single-center study using an unselected cohort with 3-year experience

BACKGROUND

To evaluate the role of a standardized first-trimester scan in screening different kinds of central nervous system malformations and to report a 3-year experience from a tertiary center using an unselected cohort.

METHODS

This was a retrospective analysis of prospectively collected data from a single center evaluating first-trimester scans with predesigned standardized protocols performed between 1 May 2017 and 1 May 2020, involving 39,526 pregnancies. All pregnant women underwent a series of prenatal ultrasound scans at 11-14, 20-24, 28-34 and 34-38 weeks of gestation. Abnormalities were confirmed by magnetic resonance imaging, postmortem examination or trained ultrasound professionals. Pregnancy outcomes and some postnatal follow-up were obtained from maternity medical records and telephone calls.

RESULTS

A total of 38,586 pregnancies included in the study. The detection rates of CNS anomalies by ultrasound in the first, second, third and late third trimester were 32%, 22%, 25%, and 16%, respectively. And there were 5% of CNS anomalies missed by prenatal ultrasound. In the first-trimester scan, we diagnosed all cases of exencephaly, anencephaly, alobar holoprosencephaly and meningoencephalocele, and some cases of posterior cranial fossa anomalies (20%), open spina bifida (67%), semilobar holoprosencephaly (75%) and severe ventriculomegaly (8%). Vein of Galen aneurysmal malformation, closed spina bifida, lobar holoprosencephaly, intracranial infection, arachnoid cyst, agenesis of the corpus callosum, cysts of the septum pellucidum and isolated absence of the septum pellucidum were never detected during the first trimester. The abortion rates of fetal CNS anomalies detected by first-trimester scan, second-trimester scan, and third- trimester scan were 96%, 84% and 14%, respectively.

CONCLUSIONS

The study showed that almost 1/3 of central nervous system anomalies were detected by the standard first-trimester scan and these cases were associated with a high rate of abortion. Early screening for fetal abnormalities gives parents more time for medical advice and safer abortion if needed. It is therefore recommended that some major CNS anomalies should be screened in the first trimester. The standardized anatomical protocol, consisting of four fetal brain planes, were recommended for routine first trimester ultrasound screening.

Routine first-trimester ultrasound screening using a standardized anatomical protocol

BACKGROUND

First-trimester ultrasound scans were introduced to China for nearly 20 years. The ability of first-trimester ultrasound screening to detect different malformations was variable. A recent systematic review concluded that the use of a standardized anatomic protocol was the most crucial factor to improve the sensitivity of first-trimester ultrasound screening for anomalies. Standardized sectional scans have long been used for routine anatomy screening during the second trimester. However, during the first trimester, most of the previous studies have described the observation of anatomic structures but have not specified clearly the standard sectional views.

OBJECTIVE

We aimed to determine the performance of routine first-trimester scans using a standardized anatomic protocol for detecting structural abnormalities in China.

STUDY DESIGN

This was a large retrospective study involving 59,063 sequential unselected pregnancies. Scans at 11 to 13⁺⁶ weeks were performed in a single center during a 7-year span. All fetuses were examined following a predefined protocol for standardized views.

RESULTS

From October 2008 to December 2015, first-trimester scans were performed in 53,349 pregnant women with available outcome. Of these, there were 1578 (3%) pregnancies that presented with at least 1 fetal structural abnormality. The detection rate for first-trimester screening was 43.1% (95% confidence interval, 40.6%-45.5%). Routine first-trimester scans detected 95.6% of abdominal wall defects, 66.3% of nervous system defects, 33.8% of limbs and skeleton malformations, 30.8% of facial abnormalities, 21.2% of urogenital abnormalities, 18.4% of thoracic and lung abnormalities, and 4.1% of gastrointestinal tract abnormalities. During the first trimester, 37.7% of cardiac defects were identified and included 57.9% of major cardiac defects and 2.6% of mild cardiac defects. A robust high detection rate for anencephaly, exencephaly, cephalocele, holoprosencephaly, exomphalos, gastroschisis, Pentalogy of Cantrell, sirenomelia, and body stalk anomaly was achieved during routine first-trimester scans.

CONCLUSION

A standardized anatomic protocol is advised when performing routine first-trimester ultrasound screening. It is recommended that screening for severe structural abnormalities should be extended to the first trimester.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

First and second trimester serum tests with and without first trimester ultrasound tests for Down's syndrome screening

BACKGROUND

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

OBJECTIVES

To estimate and compare the accuracy of first and second trimester serum markers with and without first trimester ultrasound markers for the detection of Down's syndrome in the antenatal period, as combinations of markers.

SEARCH METHODS

We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), the Database of Abstracts of Reviews of Effectiveness (the Cochrane Library 25 August 2011), MEDION (25 August 2011), the Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), the National Research Register (Archived 2007), and Health Services Research Projects in Progress database (25 August 2011). We did not apply a diagnostic test search filter. We did forward citation searching in ISI citation indices, Google Scholar and PubMed 'related articles'. We also searched reference lists of retrieved articles SELECTION CRITERIA: Studies evaluating tests of combining first and second trimester maternal serum markers in women up to 24 weeks of gestation for Down's syndrome, with or without first trimester ultrasound markers, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Twenty-two studies (reported in 25 publications) involving 228,615 pregnancies (including 1067 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high risk pregnancies. Ten studies made direct comparisons between tests. Thirty-two different test combinations were evaluated formed from combinations of eight different tests and maternal age; first trimester nuchal translucency (NT) and the serum markers AFP, uE3, total hCG, free βhCG, Inhibin A, PAPP-A and ADAM 12. We looked at tests combining first and second trimester markers with or without ultrasound as complete tests, and we also examined stepwise and contingent strategies.Meta-analysis of the six most frequently evaluated test combinations showed that a test strategy involving maternal age and a combination of first trimester NT and PAPP-A, and second trimester total hCG, uE3, AFP and Inhibin A significantly outperformed other test combinations that involved only one serum marker or NT in the first trimester, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate. However, the evidence was limited in terms of the number of studies evaluating this strategy, and we therefore cannot recommend one single screening strategy.

AUTHORS' CONCLUSIONS

Tests involving first trimester ultrasound with first and second trimester serum markers in combination with maternal age are significantly better than those without ultrasound, or those evaluating first trimester ultrasound in combination with second trimester serum markers, without first trimester serum markers. We cannot make recommendations about a specific strategy on the basis of the small number of studies available.

Urine tests for Down's syndrome screening

BACKGROUND

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

OBJECTIVES

To estimate and compare the accuracy of first and second trimester urine markers for the detection of Down's syndrome.

SEARCH METHODS

We carried out a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), EMBASE (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 2011, Issue 7), MEDION (25 August 2011), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), The National Research Register (archived 2007), Health Services Research Projects in Progress database (25 August 2011). We studied reference lists and published review articles.

SELECTION CRITERIA

Studies evaluating tests of maternal urine in women up to 24 weeks of gestation for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

We extracted data as test positive or test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria. We used hierarchical summary ROC (receiver operating characteristic) meta-analytical methods to analyse test performance and compare test accuracy. We performed analysis of studies allowing direct comparison between tests. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 19 studies involving 18,013 pregnancies (including 527 with Down's syndrome). Studies were generally of high quality, although differential verification was common with invasive testing of only high-risk pregnancies. Twenty-four test combinations were evaluated formed from combinations of the following seven different markers with and without maternal age: AFP (alpha-fetoprotein), ITA (invasive trophoblast antigen), ß-core fragment, free ßhCG (beta human chorionic gonadotrophin), total hCG, oestriol, gonadotropin peptide and various marker ratios. The strategies evaluated included three double tests and seven single tests in combination with maternal age, and one triple test, two double tests and 11 single tests without maternal age. Twelve of the 19 studies only evaluated the performance of a single test strategy while the remaining seven evaluated at least two test strategies. Two marker combinations were evaluated in more than four studies; second trimester ß-core fragment (six studies), and second trimester ß-core fragment with maternal age (five studies).In direct test comparisons, for a 5% false positive rate (FPR), the diagnostic accuracy of the double marker second trimester ß-core fragment and oestriol with maternal age test combination was significantly better (ratio of diagnostic odds ratio (RDOR): 2.2 (95% confidence interval (CI) 1.1 to 4.5), P = 0.02) (summary sensitivity of 73% (CI 57 to 85) at a cut-point of 5% FPR) than that of the single marker test strategy of second trimester ß-core fragment and maternal age (summary sensitivity of 56% (CI 45 to 66) at a cut-point of 5% FPR), but was not significantly better (RDOR: 1.5 (0.8 to 2.8), P = 0.21) than that of the second trimester ß-core fragment to oestriol ratio and maternal age test strategy (summary sensitivity of 71% (CI 51 to 86) at a cut-point of 5% FPR).

AUTHORS' CONCLUSIONS

Tests involving second trimester ß-core fragment and oestriol with maternal age are significantly more sensitive than the single marker second trimester ß-core fragment and maternal age, however, there were few studies. There is a paucity of evidence available to support the use of urine testing for Down's syndrome screening in clinical practice where alternatives are available.

First trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. However, no test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

The aim of this review was to estimate and compare the accuracy of first trimester serum markers for the detection of Down's syndrome in the antenatal period, both as individual markers and as combinations of markers. Accuracy is described by the proportion of fetuses with Down's syndrome detected by screening before birth (sensitivity or detection rate) and the proportion of women with a low risk (normal) screening test result who subsequently had a baby unaffected by Down's syndrome (specificity).

SEARCH METHODS

We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 25 August 2011), MEDION (25 August 2011), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), The National Research Register (Archived 2007), Health Services Research Projects in Progress database (25 August 2011). We did forward citation searching ISI citation indices, Google Scholar and PubMed 'related articles'. We did not apply a diagnostic test search filter. We also searched reference lists and published review articles.  

SELECTION CRITERIA

We included studies in which all women from a given population had one or more index test(s) compared to a reference standard (either chromosomal verification or macroscopic postnatal inspection). Both consecutive series and diagnostic case-control study designs were included. Randomised trials where individuals were randomised to different screening strategies and all verified using a reference standard were also eligible for inclusion. Studies in which test strategies were compared head-to-head either in the same women, or between randomised groups were identified for inclusion in separate comparisons of test strategies. We excluded studies if they included less than five Down's syndrome cases, or more than 20% of participants were not followed up.

DATA COLLECTION AND ANALYSIS

We extracted data as test positive or test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria. We used hierarchical summary ROC meta-analytical methods or random-effects logistic regression methods to analyse test performance and compare test accuracy as appropriate. Analyses of studies allowing direct and indirect comparisons between tests were undertaken.

MAIN RESULTS

We included 56 studies (reported in 68 publications) involving 204,759 pregnancies (including 2113 with Down's syndrome). Studies were generally of good quality, although differential verification was common with invasive testing of only high-risk pregnancies. We evaluated 78 test combinations formed from combinations of 18 different tests, with or without maternal age; ADAM12 (a disintegrin and metalloprotease), AFP (alpha-fetoprotein), inhibin, PAPP-A (pregnancy-associated plasma protein A, ITA (invasive trophoblast antigen), free βhCG (beta human chorionic gonadotrophin), PlGF (placental growth factor), SP1 (Schwangerschafts protein 1), total hCG, progesterone, uE3 (unconjugated oestriol), GHBP (growth hormone binding protein), PGH (placental growth hormone), hyperglycosylated hCG, ProMBP (proform of eosinophil major basic protein), hPL (human placental lactogen), (free αhCG, and free ßhCG to AFP ratio. Direct comparisons between two or more tests were made in 27 studies.Meta-analysis of the nine best performing or frequently evaluated test combinations showed that a test strategy involving maternal age and a double marker combination of PAPP-A and free ßhCG significantly outperformed the individual markers (with or without maternal age) detecting about seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). Limited evidence suggested that marker combinations involving PAPP-A may be more sensitive than those without PAPP-A.

AUTHORS' CONCLUSIONS

Tests involving two markers in combination with maternal age, specifically PAPP-A, free βhCG and maternal age are significantly better than those involving single markers with and without age. They detect seven out of 10 Down's affected pregnancies for a fixed 5% FPR. The addition of further markers (triple tests) has not been shown to be statistically superior; the studies included are small with limited power to detect a difference.The screening blood tests themselves have no adverse effects for the woman, over and above the risks of a routine blood test. However some women who have a 'high risk' screening test result, and are given amniocentesis or chorionic villus sampling (CVS) have a risk of miscarrying a baby unaffected by Down's. Parents will need to weigh up this risk when deciding whether or not to have an amniocentesis or CVS following a 'high risk' screening test result.

Improved detection rate of structural abnormalities in the first trimester using an extended examination protocol

OBJECTIVE

To assess the potential of first-trimester sonography in the detection of fetal abnormalities using an extended protocol that is achievable with reasonable resources of time, personnel and ultrasound equipment.

METHODS

This was a prospective two-center 2-year study of 5472 consecutive unselected pregnant women examined at 12 to 13 + 6 gestational weeks. Women were examined using an extended morphogenetic ultrasound protocol that, in addition to the basic evaluation, involved a color Doppler cardiac sweep and identification of early contingent markers for major abnormalities.

RESULTS

The prevalence of lethal and severe malformations was 1.39%. The first-trimester scan identified 40.6% of the cases detected overall and 76.3% of major structural defects. The first-trimester detection rate (DR) for major congenital heart disease (either isolated or associated with extracardiac abnormalities) was 90% and that for major central nervous system anomalies was 69.5%. In fetuses with increased nuchal translucency (NT), the first-trimester DR for major anomalies was 96%, and in fetuses with normal NT it was 66.7%. Most (67.1%) cases with major abnormalities presented with normal NT.

CONCLUSIONS

A detailed first-trimester anomaly scan using an extended protocol is an efficient screening method to detect major fetal structural abnormalities in low-risk pregnancies. It is feasible at 12 to 13 + 6 weeks with ultrasound equipment and personnel already used for routine first-trimester screening. Rate of detection of severe malformations is greater in early- than in mid-pregnancy and on postnatal evaluation. Early heart investigation could be improved by an extended protocol involving use of color Doppler.

Echocardiography in Early Pregnancy

Within the last decade, two significant events have contributed to the increasing interest in early fetal echocardiography. First, the introduction of high frequency vaginal ultrasound probes allows detailed visualization of cardiac structures at early stage of gestation, making early detection of fetal malformations possible. Second, the close relationship observed between some first trimester sonographic and Doppler markers and congenital heart defects allows an early identification of a high-risk group at 11 to 14 weeks of gestation. In this context, from the early 1990s, many authors have examined the potential role of the transvaginal approach to obtain earlier diagnosis of fetal cardiac malformations. Further studies have appeared in the literature showing that early transvaginal echocardiography in experienced hand is a fairly sensitive investigative tool. Although some malformations are detected as early as 11 weeks’ gestation, the optimal gestational age to perform the early scan is at least 13 weeks’ gestation. Transvaginal ultrasound is the preferred approach, although most of the authors agree that results can be improved if transabdominal ultrasound is also incorporated. The further application of color Doppler enhances visualization. The sensitivity and specificity of early fetal echocardiography for the detection of heart anomalies is acceptable compared to the ones obtained by mid-gestational echocardiography, showing a slight reduction in detection rates and an increase in false positive and negative rates. The cardiac anomalies detected at this early stage of pregnancy are mainly defects involving the four-chamber view, indicating that defects solely affecting the outflow tracts are difficult to diagnose in the first trimester of pregnancy. Heart defects diagnosed early in pregnancy tend to be more complex than those detected later, with a higher incidence of associated structural malformations, chromosomal abnormalities and spontaneous abortions. The neonate follow-up or postmortem examination in case of termination of pregnancy (TOP) is essential to assess the actual role of early fetal echocardiography. At present, early fetal echocardiography is a promising technique, which can be of considerable value for patients at high-risk. This technique is, however, currently limited to a few specialized centers.

The aim of this review is to explore the possibilities of examining the fetal heart at this early stage of pregnancy. This article also present our experience in the first multicenter trial in early fetal echocardiography performed in Spain. In accordance with other studies, this experience stresses the usefulness of early echocardiography when performed by expert operators on fetus specifically at risk for cardiac defects. Our review of these additional 48 cases contributes to the expanding literature on the ability of transvaginal ultrasonography to detect fetal heart defects in early pregnancy.

How to cite this article

Gabriel CC, Rodriguez PP. Echocardiography in Early Pregnancy. Donald School J Ultrasound Obstet Gynecol 2013;7(2):168-181.

Second trimester serum tests for Down's Syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three copies of chromosome 21 - or the specific area of chromosome 21 implicated in causing Down's syndrome - rather than two. It is the commonest congenital cause of mental retardation. Noninvasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.  

OBJECTIVES

To estimate and compare the accuracy of second trimester serum markers for the detection of Down's syndrome.

SEARCH METHODS

We carried out a sensitive and comprehensive literature search of MEDLINE (1980 to May 2007), EMBASE (1980 to 18 May 2007), BIOSIS via EDINA (1985 to 18 May 2007), CINAHL via OVID (1982 to 18 May 2007), The Database of Abstracts of Reviews of Effectiveness (The Cochrane Library 2007, Issue 1), MEDION (May 2007), The Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (May 2007), The National Research Register (May 2007), Health Services Research Projects in Progress database (May 2007). We studied reference lists and published review articles.  

SELECTION CRITERIA

Studies evaluating tests of maternal serum in women at 14-24 weeks of gestation for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

Fifty-nine studies involving 341,261 pregnancies (including 1,994 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high-risk pregnancies. Seventeen studies made direct comparisons between tests. Fifty-four test combinations were evaluated formed from combinations of 12 different tests and maternal age; alpha-fetoprotein (AFP), unconjugated oestriol (uE3), total human chorionic gonadotrophin (hCG), free beta human chorionic gonadotrophin (βhCG), free alpha human chorionic gonadotrophin (αhCG), Inhibin A, SP2, CA125, troponin, pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PGF) and proform of eosinophil major basic protein (ProMBP).Meta-analysis of 12 best performing or frequently evaluated test combinations showed double and triple tests (involving AFP, uE3, total hCG, free βhCG) significantly outperform individual markers, detecting six to seven out of every 10 Down's syndrome pregnancies at a 5% false positive rate. Tests additionally involving inhibin performed best (eight out of every 10 Down's syndrome pregnancies) but were not shown to be significantly better than standard triple tests in direct comparisons. Significantly lower sensitivity occurred in women over the age of 35 years. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting the accuracy of the sensitivity.

AUTHORS' CONCLUSIONS

Tests involving two or more markers in combination with maternal age are significantly more sensitive than those involving one marker. The value of combining four or more tests or including inhibin have not been proven to show statistically significant improvement. Further study is required to investigate reduced test performance in women aged over 35 and the impact of differential pregnancy loss on study findings.

First-trimester detection of structural abnormalities and the role of aneuploidy markers

OBJECTIVES

To determine the sensitivity of first-trimester ultrasound for diagnosing different structural anomalies in chromosomally normal pregnancies, and to establish the role of aneuploidy markers in the detection of abnormalities.

METHODS

This was a retrospective study of chromosomally normal singleton pregnancies with an 11-14-week scan performed in our center during 2002-2009. The ultrasound examination included an early fetal anatomy survey and assessment of nuchal translucency, ductus venosus blood flow and nasal bone.

RESULTS

Among 13 723 scanned first-trimester pregnancies with no genetic anomalies and complete follow-up, 439 fetuses (3.2%) were found to present with structural anomalies (194 with major anomalies and 245 with only minor anomalies). Forty-nine per cent of major structural anomalies were detected during the first-trimester scan, the highest rates corresponding to acrania (17/17), holoprosencephaly (three of three), hypoplastic left heart syndrome (10/10), omphalocele (six of six), megacystis (seven of eight) and hydrops (eight of nine). Higher than expected detection rates were obtained for skeletal (69%) and cardiac (57%) defects, coincidentally showing the highest presence of an increased nuchal translucency or abnormal ductus venosus blood flow (38% and 52%, respectively). The finding of an absent nasal bone did not appear to be associated with structural defects.

CONCLUSION

About half of major structural abnormalities can be diagnosed in the first trimester. Increased nuchal translucency or abnormal ductus venosus blood flow appear to be associated with cardiac and skeletal defects and may facilitate early detection.

13-14-week fetal anatomy scan: a 5-year prospective study

OBJECTIVES

To assess the potential value of an early (first-trimester) ultrasound examination in depicting fetal anomalies by transabdominal (TAS) and transvaginal (TVS) sonography, to compare it with the traditional mid-trimester anomaly ultrasound examination and to evaluate the degree of patient acceptance of early sonography by the transvaginal route.

METHODS

In this prospective study over a 5-year period (January 2002 to January 2007) 2876 pregnant women underwent a 13-14-week ultrasound examination. The scan was performed by TAS at first and then, if a full fetal anatomical survey was not achieved, by TVS. A mid-trimester fetal anatomy scan was then performed in patients who had not dropped out, miscarried or undergone pregnancy termination (n = 2834).

RESULTS

In the early scan, analyzable data for 2876 TAS and 1357 TVS examinations showed that TVS was significantly better in visualizing the cranium, spine, stomach, kidneys, bladder and upper and lower limbs (P < 0.001). Complete fetal anatomical surveys were achieved by TAS in 64% of cases versus 82% of the cases in which it was attempted by TVS (P < 0.001). Patient body mass index significantly affected the ability of the sonographer to achieve a complete anatomical survey by both TAS and TVS (P < 0.001 and P = 0.004, respectively). The duration of the scan was significantly longer using TVS. The heart and kidneys were not properly visualized in 42% and 27% of cases, respectively, at the 13-week scan compared with 1.6% and 0% at the mid-trimester scan. The total number of cases in which anomalies were detected was 31. At the first-trimester scan, anomalies were detected in 21 fetuses and in 14 of these cases the parents chose pregnancy termination. At the second-trimester scan, anomalies were detected in 17 fetuses: 10 new anomalous cases along with seven cases already detected in the first-trimester scan.

CONCLUSION

Besides its importance in screening for chromosomal abnormalities, the early scan has great potential in visualizing with precision fetal anatomy. TVS can be used to compliment difficult TAS examinations; however, patients do not always agree to undergo TVS. The mid-trimester scan remains crucial for detailed fetal anatomical survey.

Sonoembryology and early prenatal diagnosis of neural anomalies

In the following review, the early development of the central nervous system (CNS), as described by embryologists and anatomists in modern embryological textbooks, is compared with sonoanatomic descriptions from two-dimensional (2D) and three-dimensional (3D) ultrasound studies, week by week in the first trimester. The anatomic descriptions are limited to details that are of interest for the understanding of ultrasound examinations. Further, the detection of main CNS anomalies including spina bifida during the first trimester are presented and discussed. Empty or enlarged brain cavities, or abnormal contours of the head and spine are important diagnostic markers for the detection of CNS anomalies in the very early pregnancy.

Performing a fetal anatomy scan at the time of first-trimester screening

Over the past decade, prenatal diagnosis has shifted rapidly from the second trimester into the first trimester. Although the nuchal-translucency scan may detect a small proportion of fetal structural malformations, fetal anatomy is not routinely assessed until the fetal anatomical survey is performed in the second trimester between 18 and 22 weeks. The recent development of high-frequency transvaginal ultrasound transducers has led to vastly improved ultrasound resolution and improved visualization of fetal anatomy earlier in gestation. Several pilot studies of a first-trimester anatomic survey have reported detection rates comparable with those achieved in the routine second-trimester anatomic survey. As advanced ultrasound technology becomes more available, there is an urgent need to evaluate the diagnostic ability of a first-trimester anatomic survey and to determine the role of a first-trimester anatomic survey in the current screening paradigm.

Detection of malformations in chromosomally normal fetuses by routine ultrasound at 12 or 18 weeks of gestation-a randomised controlled trial in 39,572 pregnancies

OBJECTIVE

To compare the antenatal detection rate of malformations in chromosomally normal fetuses between a strategy of offering one routine ultrasound examination at 12 gestational weeks (gws) and a strategy of offering one routine examination at 18 gws.

DESIGN

Randomised controlled trial.

SETTING

Multicentre trial including eight hospitals.

POPULATION

A total of 39,572 unselected pregnant women.

METHODS

Women were randomised either to one routine ultrasound scan at 12 (12-14) gws including nuchal translucency (NT) measurement or to one routine scan at 18 (15-22) gws. Anomaly screening was performed in both groups following a check-list. A repeat scan was offered in the 12-week scan group if the fetal anatomy could not be adequately seen at 12-14 gws or if NT was >or=3.5 mm in a fetus with normal or unknown chromosomes.

MAIN OUTCOME MEASURES

Antenatal detection rate of malformed fetuses.

RESULTS

The antenatal detection rate of fetuses with a major malformation was 38% (66/176) in the 12-week scan group and 47% (72/152) in the 18-week scan group (P= 0.06). The corresponding figures for detection at <22 gws were 30% (53/176) and 40% (61/152) (P= 0.07). In the 12-week scan group, 69% of fetuses with a lethal anomaly were detected at a scan at 12-14 gws.

CONCLUSIONS

None of the two strategies for prenatal diagnosis is clearly superior to the other. The 12-week strategy has the advantage that most lethal malformations will be detected at <15 gws, enabling earlier pregnancy termination. The 18-week strategy seems to be associated with a slightly higher detection rate of major malformations, although the difference was not statistically significant.

[Role of "subtle" ultrasonographic signs during antenatal screening for trisomy 21 during the second trimester of pregnancy: meta-analysis and CPDPN protocol of the Grenoble University Hospital]

OBJECTIVE

A meta-analysis about subtle ultrasonographic signs in second trimester of pregnancy.

MATERIALS AND METHODS

196 articles dealing with the subject--from 1985 to July 2002--were studied. Data on the 11 reported signs were collected from 92 theoretically and/or statistically valid studies. Then, the studies were selected according to several criteria: isolated characteristic, defined thresholds, calculable sensitivity and specificity. After checking for homogeneity, a likelihood ratio was calculated for some of the signs.

RESULTS

This meta-analysis of the second trimester ultrasonographic signs of Down's syndrome enabled us to estimate the likelihood ratio (LHR) of six signs. At 22 weeks'gestation (WG) these signs are: pyelectasis equal to or greater than 5 mm; nuchal fold thickness equal to or greater than 6 mm; persistence of choroid plexus cysts; shortness of the femur and humerus below the tenth percentile; hyperechogenic bowe; and nasal bone length less than 2.5 mm.

CONCLUSION

These validated ultrasonographic signs are independent of nuchal translucency thickness at 12 WG and of maternal serum biochemistry. This allows to calculate a combinate risk for nuchal translucency, maternal serum biochemistry and second trimester ultrasonographic signs when they are validated.

Early detection of fetal structural abnormalities

Most published data on the detection of fetal anomalies at 11-14 weeks are from specialized centres with considerable experience in fetal anomaly scanning. However, there is still limited information on the feasibility and limitations of the screening of these anomalies compared with the now classical mid-gestation screening. This review indicates that overall, the detection rate of fetal anomalies at 11-14 weeks is 44% compared with 74% by the mid-pregnancy scan. Major abnormalities of the fetal head, abdominal wall and urinary tract, and of the umbilical cord and placenta, can be reliably detected at 10-11 weeks of gestation. Detection of other anomalies such as spina bifida, diaphragmatic hernia or heart defects is limited before 13 weeks of gestation. So far it cannot be stated that routine first trimester screening can be used on a large scale to evaluate the fetal spine and heart in the general population. In particular, in screening for congenital heart defects, the ability to perform a full cardiac examination increases from 20% at 11 weeks to 92% at 13 weeks. The early prenatal diagnosis of these anomalies may be improved by screening at 13-14 weeks rather than during the first trimester.

Qualified and trained sonographers in the US can perform early fetal anatomy scans between 11 and 14 weeks

OBJECTIVES

The objective of this study was to determine the extent to which normal fetal anatomy can be detected between 11- and 14-week scan by sonographers in the US.

STUDY DESIGN

In a prospective cross-sectional study, 223 unselected women underwent a detailed assessment of fetal anatomy at 11 to 13 and 6/7 weeks by sonographers with transabdominal and/or transvaginal transducers. Thirty-seven structures were examined. Two groups were identified: group I: 121 patients between 11 and 12 weeks, and group II: 102 patients between 13 and 14 weeks.

RESULTS

Structures other than the posterior fossa, heart, genitalia, and the sacral spine were seen between 64% to 99% for group I, and 72% to 98% for group II. The following structures were detected with statistically significantly higher rates in group II compared with group I: cerebellum, posterior fossa, face, 4-chamber view left ventricular outflow tract, aortic arch, ductal arch, kidneys, and genitalia. Comparing the patients of group I and group II, the transvaginal scans yielded a higher detection rate of structures than do the transabdominal scans.

CONCLUSION

Anatomic surveys between 11 and 14 weeks can be performed by sonographers with good detection rates of most structures. Using the vaginal probe compared with the abdominal probe improved the detection rate at 13 to 14 weeks as well as 11 to 12 weeks. If early fetal structure evaluation is to become customary in the US, the present practice of experienced and trained sonographers to scan such patients can be maintained.

First-trimester sonographic diagnosis of holoprosencephaly: value of the "butterfly" sign

OBJECTIVE

To study the value of choroid plexus dysmorphology as a screening tool for the first-trimester sonographic diagnosis of holoprosencephaly in a high-risk population.

METHODS

A total of 378 consecutive pregnancies undergoing chorionic villus sampling between 11 and 14 weeks' gestation were scanned before the procedure, following the recommendations of the Fetal Medicine Foundation (London, England). A cross-sectional view of the fetal brain, including the visualization of both choroid plexuses (the "butterfly" sign), was obtained in all cases.

RESULTS

There were 3 cases in which the butterfly sign was not identified. In these cases, the first-trimester diagnosis of holoprosencephaly was confirmed by the presence of a single monoventricular cavity and fused thalami. Two of these fetuses had features of facial dysmorphism at the time of presentation and 2 had extracranial anomalies, including a cystic hygroma in 1 and a small omphalocele and polydactyly in another. Chromosomal analysis showed trisomy 13 in 2 cases and a ring chromosome 13 in the other.

CONCLUSIONS

This series suggests that failure to identify the butterfly sign is a warning sign of holoprosencephaly in the first trimester. Systematic identification of the butterfly sign at the time of sonographic assessment of nuchal translucency provides a valuable tool for the early screening of holoprosencephaly.

Ultrasound in prenatal diagnosis: polemics around routine ultrasound screening for second trimester fetal malformations

Ultrasound for routine fetal malformation screening has been polemical from its early beginning because of the very broad range of diagnosis rates disclosed, i.e. from 13% to 82%, average 27.5%. A review of available studies is proposed to assess objectively the efficacy of ultrasound, considering also economical, ethical and methodological aspects as influential factors for choosing a routine screening policy. The utility of fetal malformation diagnosis before birth is brought forward, including second opinion, karyotyping, poly-disciplinary case discussion prior to management. Method and material of reviewed studies considerably vary and might influence the sensitivity results, as the choice of the population sample and selection of pregnant women, gestation age at screening, distribution of malformation among systems or tracts, exclusion of some fetal malformation and the routine practice of autopsy. Efficiency of screening studies is compared, and among them Radius and Eurofetus studies. Average sensitivity is finally considered as satisfactory in the daily practice when operated by trained personnel. The importance of additional factors for successful screening are emphasized such as education, equipment quality and fetal ultrasound examination at different gestation age for a better understanding of natural history of fetal morphology.

First-trimester ultrasound

There has been an increase in the use of fetal ultrasound in the first trimester. This article reviews the published literature with emphasis on fetal nuchal translucency (NT). When measured according to well-defined guidelines, increased NT identifies about 80% of chromosomal anomalies for a false-positive rate of about 5%. Increased NT may indicate the presence of structural defects or genetic disorders, and it is relatively frequently seen in monochorionic pregnancies prone to develop twin-twin transfusion syndrome.

Ultrasonic markers of fetal chromosomal abnormalities

OBJECTIVE

The aim of this brief investigation was to correlate the most common sonographically detectable markers with certain type of chromosomal disorder diagnosed by available karyotyping procedures.

STUDY DESIGN

During the 3 year study period fetal karyotyping was performed in 1055 patients for a variety of clinical indication. Twenty one percent (21%; 222/1055) of procedures were done because of sonographically detectable structural disorders related to phenotype expression of chromosomopathies. Sonographic examinations and karyotyping procedures were performed between the 10th and 36th week. The average maternal age was 27 years, unselected.

RESULTS

The fetal karyotype was abnormal in 13.5% of cases (30/222). Within the group of single marker, 11.6% (7/60) of karyotypes were abnormal. Multiple markers of chromosomal abnormalities resulted in 14.2% (23/162) of abnormal karyotypes. The most frequent chromosomal disorder detected in sonographic screening is trisomy 18 (50%; 15/30). The data on the frequency of different types of chromosomal abnormalities are given.

CONCLUSIONS

The incidence of chromosomal abnormalities for ultrasonographically detectable malformations is much higher than the incidence reported in screening studies based on maternal age or biochemical screening. Trisomy 21 showed the relative lack of variety in phenotypic expression, and nuchal translucency screening has to be accepted rationally. Associated numerous major and minor malformations were the most prominent factors leading to the diagnosis of chromosomopathies, particularly trisomy 18.