Performance of a targeted cell-free DNA prenatal test for 22q11.2 deletion in a large clinical cohort.

OBJECTIVE: 22q11.2 deletion is more common than trisomies 18 and 13 combined, yet no routine approach to prenatal screening for this microdeletion has been established. This study evaluated the clinical sensitivity and specificity of a targeted cell-free DNA (cfDNA) test to screen for fetal 22q11.2 deletion in a large cohort, using blinded analysis of prospectively enrolled pregnancies and stored clinical samples. METHODS: In order to ensure that the analysis included a meaningful number of cases with fetal 22q11.2 deletion, maternal plasma samples were obtained by prospective, multicenter enrolment of pregnancies with a fetal cardiac abnormality and from stored clinical samples from a research sample bank. Fetal genetic status, as evaluated by microarray analysis, karyotyping with fluorescence in-situ hybridization or a comparable test, was available for all cases. Samples were processed as described previously for the Harmony prenatal test, with the addition of DANSR (Digital Analysis of Selected Regions) assays targeting the 3.0-Mb region of 22q11.2 associated with 22q11.2 deletion syndrome. Operators were blinded to fetal genetic status. Sensitivity and specificity of the cfDNA test for 22q11.2 deletion were calculated based on concordance between the cfDNA result and fetal genotype. RESULTS: The final study group consisted of 735 clinical samples, including 358 from prospectively enrolled pregnancies and 377 stored clinical samples. Of 46 maternal plasma samples from pregnancies with a 22q11.2 deletion, ranging in size from 1.25 to 3.25 Mb, 32 had a cfDNA result indicating a high probability of 22q11.2 deletion (sensitivity, 69.6% (95% CI, 55.2-80.9%)). All 689 maternal plasma samples without a 22q11.2 deletion were classified correctly by the cfDNA test as having no evidence of a 22q11.2 deletion (specificity, 100% (95% CI, 99.5-100%)). CONCLUSIONS: The results of this large-scale prospective clinical evaluation of the sensitivity and specificity of a targeted cfDNA test for fetal 22q11.2 deletion demonstrate that this test can detect the common and smaller, nested 22q11.2 deletions with a low (0-0.5%) false-positive rate. Although the positive predictive value (PPV) observed in this study population was 100%, the expected PPV in the general pregnant population is estimated to be 12.2% at 99.5% specificity and 41.1% at 99.9% specificity. The use of this cfDNA test to screen for 22q11.2 deletion could enhance identification of pregnancies at risk for 22q11.2 deletion syndrome without significantly increasing the likelihood of maternal anxiety and unnecessary invasive procedures related to a false-positive result. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

State-wide utilization and performance of traditional and cell-free DNA-based prenatal testing pathways: the Victorian Perinatal Record Linkage (PeRL) study.

OBJECTIVES: To perform individual record linkage of women undergoing screening with cell-free DNA (cfDNA), combined first-trimester screening (CFTS), second-trimester serum screening (STSS), and/or prenatal and postnatal cytogenetic testing with the aim to (1) obtain population-based estimates of utilization of prenatal screening and invasive diagnosis, (2) analyze the performance of different prenatal screening strategies, and (3) report the residual risk of any major chromosomal abnormality following a low-risk aneuploidy screening result. METHODS: This was a retrospective study of women residing in the state of Victoria, Australia, who underwent prenatal screening or invasive prenatal diagnosis in 2015. Patient-funded cfDNA referrals from multiple providers were merged with state-wide results for government-subsidized CFTS, STSS and invasive diagnostic procedures. Postnatal cytogenetic results from products of conception and infants up to 12 months of age were obtained to ascertain cases of false-negative screening results and atypical chromosomal abnormalities. Individual record linkage was performed using LinkageWizTM . RESULTS: During the study period, there were 79 140 births and 66 166 (83.6%) women underwent at least one form of aneuploidy screening. Linkage data were complete for 93.5% (n = 61 877) of women who underwent screening, and of these, 73.2% (n = 45 275) had CFTS alone, 20.2% (n = 12 486) had cfDNA alone; 5.3% (n = 3268) had STSS alone, 1.3% (n = 813) had both CFTS and cfDNA, and < 0.1% (n = 35) had both STSS and cfDNA. CFTS had a combined sensitivity for trisomies 21 (T21), 18 (T18) and 13 (T13) of 89.57% (95% CI, 82.64-93.93%) for a screen-positive rate (SPR) of 2.94%. There were 12 false-negative results in the CFTS pathway, comprising 10 cases of T21, one of T18 and one of T13. cfDNA had a combined sensitivity for T21, T18 and T13 of 100% (95% CI, 95.00-100%) for a SPR of 1.21%. When high-risk cfDNA results for any chromosome (including the sex chromosomes) and failed cfDNA tests were treated as screen positives, the SPR for cfDNA increased to 2.42%. The risk of any major chromosomal abnormality (including atypical abnormalities) detected on prenatal or postnatal diagnostic testing after a low-risk screening result was 1 in 1188 for CFTS (n = 37) and 1 in 762 for cfDNA (n = 16) (P = 0.13). The range of chromosomal abnormalities detected after a low-risk cfDNA result included pathogenic copy-number variants (n = 6), triploidy (n = 3), rare autosomal trisomies (n = 3) and monosomy X (n = 2). CONCLUSIONS: Our state-wide record-linkage analysis delineated the utilization and clinical performance of the multitude of prenatal screening pathways available to pregnant women. The sensitivity of cfDNA for T21, T18 and T13 was clearly superior to that of CFTS. While there was no statistically significant difference in the residual risk of any major chromosomal abnormality after a low-risk CFTS or cfDNA result, there were fewer live infants diagnosed with a major chromosomal abnormality in the cfDNA cohort. These data provide valuable population-based evidence to inform practice recommendations and health policies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Comparison of management regimens following ultrasound diagnosis of nontubal ectopic pregnancies: a retrospective cohort study.

OBJECTIVE: To review management options for nontubal ectopic pregnancies. DESIGN: Retrospective cohort study. SETTING: Tertiary hospital in Melbourne, Australia. POPULATION: A total of 100 nontubal pregnancies: 1 abdominal, 32 caesarean scar, 14 cervical, 41 cornual-interstitial, 12 ovarian. METHODS: Cases were classified according to ectopic site. Management categories were medical, surgical, combination or expectant. Use of minimally invasive approaches (ultrasound-guided intra-sac injections or selective surgical techniques) was identified. Primary management was considered to be successful if no further unplanned interventions were required. MAIN OUTCOME MEASURES: Success of primary management and frequency of unplanned interventions. RESULTS: A high rate of success (82%) was demonstrated for all management regimens, with minimal morbidity and no deaths occurring. A high success rate was shown when the primary management regimen was systemic methotrexate or ultrasound-guided intra-sac injection (88%). The success rate for primary surgical management was 57%. High success rates were reported for both primary management with ultrasound-guided injections or in combination with systemic methotrexate (94%) and for primary management with systemic methotrexate alone (81%). Seventy-five per cent of women managed with minimally invasive surgical approaches avoided the need for more extensive surgery, but required longer follow up and additional interventions. CONCLUSION: Minimally invasive approaches were found to be safe and effective treatment for women desiring to conserve fertility. Ultrasound-guided intra-sac injection and laparoscopic ectopic removal procedures aimed at preserving reproductive organs should be included as minimally invasive primary management tools in addition to the well-recognised option of systemic methotrexate. TWEETABLE ABSTRACT: Nontubal ectopics: minimally invasive procedures a safe alternative to surgery in selected cases.

Congenital heart disease and adverse perinatal outcome in fetuses with confirmed isolated single functioning umbilical artery.

To examine the association between isolated single umbilical artery (SUA) and congenital heart disease/adverse perinatal outcome in an Australian tertiary centre. The study population was comprised of fetuses diagnosed with SUA at the mid-trimester scan between May 2003 and March 2009 during detailed ultrasound examination at The Royal Women's Hospital Melbourne, Australia. Colour Doppler was used to visualise the umbilical arteries adjacent to the fetal bladder and in a section of a free loop of cord. The diagnosis of SUA was confirmed on histopathology examination of the placenta and umbilical cord. Monochorionic twins, fetuses with chromosomal abnormalities or concurrent extracardiac anomalies were excluded from the study. A total of 261 fetuses with SUA were identified in the study period and 146 (59%) cases were isolated; no chromosomal or extracardiac abnormalities were present. Complete data were available in 104/146 pregnancies (71.2%). The mean gestational age at diagnosis was 21 weeks. A cardiac anomaly was detected in 19 of these fetuses (13.0%): six hypoplastic left heart syndromes; three coarctations of the aorta; two tetralogies of Fallot; two hypoplastic right heart syndromes; two pulmonary atresia/stenosis; one absent ductus venosus with cardiomegaly; one left isomerism; one right isomerism and one transposition of the great arteries. Fetal growth restriction was present in 9.8% (10) and preterm delivery before 34 weeks occurred in nine cases (8.7%). Our study has shown that isolated SUA is associated with cardiac anomalies, but is not associated with increased frequency of FGR and preterm delivery before 34 weeks.

Meeting the challenge of interpreting high-resolution single nucleotide polymorphism array data in prenatal diagnosis: does increased diagnostic power outweigh the dilemma of rare variants?

OBJECTIVE: Several studies have already shown the superiority of chromosomal microarray analysis (CMA) compared with conventional karyotyping for prenatal investigation of fetal ultrasound abnormality. This study used very high-resolution single nucleotide polymorphism (SNP) arrays to determine the impact on detection rates of all clinical categories of copy number variations (CNVs), and address the issue of interpreting and communicating findings of uncertain or unknown clinical significance, which are to be expected at higher frequency when using very high-resolution CMA. DESIGN: Prospective validation study. SETTING: Tertiary clinical genetics centre. POPULATION: Women referred for further investigation of fetal ultrasound anomaly. METHODS: We prospectively tested 104 prenatal samples using both conventional karyotyping and high-resolution arrays. MAIN OUTCOME MEASURES: The detection rates for each clinical category of CNV. RESULTS: Unequivocal pathogenic CNVs were found in six cases, including one with uniparental disomy (paternal UPD 14). A further four cases had a 'likely pathogenic' finding. Overall, CMA improved the detection of 'pathogenic' and 'likely pathogenic' abnormalities from 2.9% (3/104) to 9.6% (10/104). CNVs of 'unknown' clinical significance that presented interpretational difficulties beyond results from parental investigations were detected in 6.7% (7/104) of samples. CONCLUSIONS: Increased detection sensitivity appears to be the main benefit of high-resolution CMA. Despite this, in this cohort there was no significant benefit in terms of improving detection of small pathogenic CNVs. A potential disadvantage is the high detection rate of CNVs of 'unknown' clinical significance. These findings emphasise the importance of establishing an evidence-based policy for the interpretation and reporting of CNVs, and the need to provide appropriate pre- and post-test counselling.

Perinatal outcomes following the ultrasound diagnosis of echogenic bowel: an Australian perspective.

INTRODUCTION: The aim of this study was to describe the association between fetal echogenic bowel (FEB) diagnosed during the second trimester and adverse perinatal outcomes in an Australian antenatal population. METHODS: A retrospective analysis of ultrasound scans was performed between March 1, 2004 and March 1, 2009 at The Royal Women's Hospital, Melbourne, Vic., Australia. Cases reported as having FEB on second trimester ultrasound were included. Medical records of each case were reviewed and information concerning additional investigations and perinatal outcomes were extracted. RESULTS: A total of 66 cases were identified in our database. Three patients (5%) were excluded from further analysis as they were lost to follow-up, leaving 63 (95%) cases in this series. Thirty-two fetuses (52%) underwent karyotyping via amniocentesis, 5 (16%) of which were found to have chromosomal defects. Maternal serology for cytomegalovirus (CMV) was performed in 49 (78%) cases. Investigations indicated a total of 5 women who had CMV infection during their pregnancy. Thirty-three pregnancies (53%) were tested for cystic fibrosis (CF) and 1 baby was confirmed to have CF postnatally. Among the 50 liveborn infants, 3 cases of fetal growth restriction were apparent. Overall, 42 of the 50 liveborn infants (84%) and 67% of the entire cohort of 63 patients with a midtrimester diagnosis of FEB had a normal short-term neonatal outcome. CONCLUSION: This study reiterates the increased prevalence of aneuploidy, CMV, CF and fetal growth restriction in pregnancies complicated by the midtrimester sonographic finding of FEB. However, reassuringly, 67% of cases with ultrasound-detected echogenic bowel in the second trimester had a normal short-term neonatal outcome in this multiethnic Australian population.

Severe fetal hydrocephalus with and without neural tube defect: a comparative study.

OBJECTIVE: To describe the main perinatal and 1-year outcomes in babies with a prenatal ultrasonographic diagnosis of severe hydrocephalus according to the presence or absence of a neural tube defect (NTD) in a country where abortion is illegal. METHOD: The study population consisted of cases referred to and delivered at Hospital de Clínicas de Porto Alegre, diagnosed between January 1993 and December 2001. The diagnosis of severe hydrocephalus was based on a lateral ventricular atrium diameter > or =15 mm in at least one hemisphere. RESULTS: Sixty cases were ascertained: 28 with NTD (group 1) and 32 without NTD (group 2). The groups were similar in terms of maternal and child variables at birth and hospitalization days during the 1st year of life. The mortality (including intrauterine deaths and deaths of babies with malformations incompatible with life that characterize a very poor prognosis) until 1 year of age was 36% in group 1 and 59% in group 2 (p = 0.077). The rate of cardiac malformations was higher in the group without NTD (p = 0.015). The length of hospital stay after birth (1st admission) was significantly higher in the group with NTD (p = 0.007). CONCLUSIONS: The morbidity was higher in the group with NTD, possibly due to the higher number of surgical interventions in the central nervous system. However, the mortality was higher in the group without NTD, possibly due to the presence of other associated malformations, especially congenital heart disease. Further studies should focus on neurological function and quality of life of the children and their families at the end of the 1st year and after 2 or 6 years of age.

Subendometrial power Doppler quantification: a new classification proposal.

Fifty-two women with regular menses were enrolled in the study. The patients were not allowed to use non-steroidal anti-inflammatory drugs within 24 h of any examination. All patients were examined during the mid-luteal phase (6-9 days after ovulation, according to previous ultrasound record). Power Doppler energy levels were classified into five categories according to the per cent area of sub-endometrial signal: I (<10%), II (10-25%), III (25-50%), IV (50-75%) and V (>75%). The colour Doppler signal was considered positive when it reached at least the endometrial basal layer. The picture of the endometrium was analysed and the regions of interest were identified and marked for further analysis. Each recorded image was then independently evaluated and classified by three blinded observers. According to the power Doppler classification, age, body mass index (BMI) and endometrial thickness were analysed, and no significant differences were observed among them. The Kappa test (0.70) demonstrated an excellent agreement among examiners (P = 0.0001). This study has validated a very simple and cost-effective classification for sub-endometrial vascularization. This method of quantification may potentially be of use, and its relevance to clinical practice should be explored.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length ú15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5 percent of cases it was 15 mm or less. The proportion of women with a short cervix (<=15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history.

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length pound 15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5% of cases it was 15 mm or less. The proportion of women with a short cervix (< or =15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Randomized controlled trial using low-dose aspirin in the prevention of pre-eclampsia in women with abnormal uterine artery Doppler at 23 weeks' gestation.

OBJECTIVE: Pre-eclampsia, which is a major cause of perinatal and maternal morbidity and mortality, is thought to be due to impaired perfusion of the placenta. There is contradictory evidence that the administration of low-dose aspirin may provide effective prophylaxis against the subsequent development of pre-eclampsia. In this study we tested the hypothesis that in women identified as being at high-risk for pre-eclampsia, because of impaired flow in the uterine arteries, the prophylactic use of low-dose aspirin from 23 weeks of gestation can reduce the incidence of pre-eclampsia. METHODS: We used color and pulsed Doppler to measure the flow in the uterine arteries in 19,950 singleton pregnancies at 22-24 weeks of gestation. Those women exhibiting increased impedance were recruited into a randomized study of aspirin 150 mg per day or placebo. We compared the two groups for the incidence of pre-eclampsia and the other consequences of impaired placentation. RESULTS: The screening study identified 844 women (4.2%) as being at high risk of uteroplacental insufficiency. After exclusion and refusal, 560 women were randomly allocated to aspirin 150 mg or placebo per day until 36 weeks' gestation. There were no significant differences between the aspirin and placebo groups in either the incidence of pre-eclampsia (18% vs. 19%, P = 0.6) or pre-eclampsia requiring delivery below 34 weeks (6% vs. 8%, P = 0.36). Furthermore, the administration of aspirin did not significantly alter the incidence of preterm delivery (24% vs. 27%, P = 0.46), birth weight below the 5th centile (22% vs. 24%, P = 0.4), perinatal death (3% vs. 1%, P = 0.33) or placental abruption (4% vs. 2%, P = 0.12). CONCLUSION: In pregnancies with impaired placentation, as demonstrated by increased impedance to flow in the uterine arteries, the daily administration of 150 mg aspirin after 23 weeks of gestation does not prevent the subsequent development of pre-eclampsia.

Prenatal diagnosis of a benign facial tumor.

We report a case of prenatal diagnosis of a benign fetal skin tumor on the chin made at 27 weeks of pregnancy by ultrasound scan. We report this case given the uncommon diagnosis and the unique fetal facial profile seen on ultrasound, resembling the image of an ancient Egyptian pharaoh which made us call it 'Ramses' sign' as a future mnemonic aid to sonographers.

Maternal hyperphenylalaninaemia as a cause of microcephaly and mental retardation.

We attempted to evaluate the role of maternal hyperphenylalaninaemia (HPA) as an isolated cause of mental retardation and microcephaly in children. This transversal study observed the plasma phenylalanine from mothers of 161 children with mental retardation and/or microcephaly of unknown origin. In this sample, we found two women with previously undiagnosed HPA, a frequency (2/161) higher than expected for our general population (1:12 500) (p < 0.001). We concluded that the plasma phenylalanine levels should be determined during preconceptional evaluation of every woman of reproductive age that already has had a child affected either by mental retardation or microcephaly of unknown cause. It is particularly significant where women currently having their pregnancies have not been screened for phenylketonuria as newborns, as happens in most developing countries.