Variants of uncertain significance in prenatal microarrays: a retrospective cohort study.

OBJECTIVE: To categorise the variants of uncertain significance found with prenatal chromosomal microarray and determine the proportion of such variants that are associated with a well-known phenotype in order to establish how often they remain truly of uncertain significance. DESIGN: Retrospective cohort study. SETTING: The University of California, San Francisco. POPULATION: All patients with a variant of uncertain significance on prenatal microarray between 2014 and 2018. METHODS: Each variant was classified as a copy number variant that (a) contains Online Mendelian Inheritance in Man (OMIM)-annotated disease-causing genes ('OMIM morbid genes'); (b) confers autosomal recessive carrier status; (c) is associated with incomplete penetrance; (d) is >1 Mb in size without OMIM morbid genes; (e) demonstrates mosaicism; or (f) contains significant regions of homozygosity. For each variant of uncertain significance, we examined the existing literature to determine whether the predicted phenotype(s) was known. MAIN OUTCOME MEASURE: Prevalence and classification of variants and how much information is available regarding the likelihood of an affected phenotype. RESULTS: Of 970 prenatal microarrays, 55 (5.8%) had at least one variant of uncertain significance. The most common were copy number variants containing OMIM morbid genes (36.8%). In all, 48 (84.2%) were associated with a known phenotype; 55 (96.5%) had data available regarding the likelihood of an affected phenotype. CONCLUSIONS: The prevalence of variants of uncertain significance with prenatal microarray was 5.8%. In the large majority of cases, data were available regarding the predicted phenotype. TWEETABLE ABSTRACT: Variants of uncertain significance occur in 5.8% of prenatal microarrays. In the overwhelming majority of cases, outcome information is available.

United States' experience in nuchal translucency measurement: variation according to provider characteristics in over five million ultrasound examinations.

OBJECTIVE: The Nuchal Translucency Quality Review (NTQR) program has provided standardized education, credentialing and epidemiological monitoring of nuchal translucency (NT) measurements since 2005. Our aim was to review the effect on NT measurement of provider characteristics since the program's inception. METHODS: We evaluated the distribution of NT measurements performed between January 2005 and December 2019, for each of the three primary performance indicators of NT measurement (NT median multiples of the median (MoM), SD of log10 NT MoM and slope of NT with respect to crown-rump length (CRL)) for all providers within the NTQR program with more than 30 paired NT/CRL results. Provider characteristics explored as potential sources of variability included: number of NT ultrasound examinations performed annually (annual scan volume of the provider), duration of participation in the NTQR program, initial credentialing by an alternative pathway, provider type (physician vs sonographer) and number of NT-credentialed providers within the practice (size of practice). Each of these provider characteristics was evaluated for its effect on NT median MoM and geometric mean of the NT median MoM weighted for the number of ultrasound scans, and multiple regression was performed across all variables to control for potential confounders. RESULTS: Of 5 216 663 NT measurements from 9340 providers at 3319 sites, the majority (75%) of providers had an NT median MoM within the acceptable range of 0.9-1.1 and 85.5% had NT median MoM not statistically significantly outside this range. Provider characteristics associated with measurement within the expected range of performance included higher volume of NT scans performed annually, practice at a site with larger numbers of other NT-credentialed providers, longer duration of participation in the NTQR program and alternative initial credentialing pathway. CONCLUSIONS: Annual scan volume, duration of participation in the NTQR program, alternative initial credentialing pathway and number of other NT-credentialed providers within the practice are all associated with outcome metrics indicating quality of performance. It is critical that providers participate in ongoing quality assessment of NT measurement to maintain consistency and precision. Ongoing assessment programs with continuous feedback and education are necessary to maintain quality care. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal hydrops and the Incremental yield of Next-generation sequencing over standard prenatal Diagnostic testing (FIND) study: prospective cohort study and meta-analysis.

OBJECTIVE: To determine the incremental yield of exome sequencing (ES) over chromosomal microarray analysis (CMA) or karyotyping in prenatally diagnosed non-immune hydrops fetalis (NIHF). METHODS: A prospective cohort study (comprising an extended group of the Prenatal Assessment of Genomes and Exomes (PAGE) study) was performed which included 28 cases of prenatally diagnosed NIHF undergoing trio ES following negative CMA or karyotyping. These cases were combined with data from a systematic review of the literature. MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched electronically (January 2000 to October 2020) for studies reporting on the incremental yield of ES over CMA or karyotyping in fetuses with prenatally detected NIHF. Inclusion criteria for the systematic review were: (i) at least two cases of NIHF undergoing sequencing; (ii) testing initiated based on prenatal ultrasound-based phenotype; and (iii) negative CMA or karyotyping result. The incremental diagnostic yield of ES was assessed in: (i) all cases of NIHF; (ii) isolated NIHF; (iii) NIHF associated with an additional fetal structural anomaly; and (iv) NIHF according to severity (i.e. two vs three or more cavities affected). RESULTS: In the extended PAGE study cohort, the additional diagnostic yield of ES over CMA or karyotyping was 25.0% (7/28) in all NIHF cases, 21.4% (3/14) in those with isolated NIHF and 28.6% (4/14) in those with non-isolated NIHF. In the meta-analysis, the pooled incremental yield based on 21 studies (306 cases) was 29% (95% CI, 24-34%; P < 0.00001; I2 = 0%) in all NIHF, 21% (95% CI, 13-30%; P < 0.00001; I2 = 0%) in isolated NIHF and 39% (95% CI, 30-49%; P < 0.00001; I2 = 1%) in NIHF associated with an additional fetal structural anomaly. In the latter group, congenital limb contractures were the most prevalent additional structural anomaly associated with a causative pathogenic variant, occurring in 17.3% (19/110) of cases. The incremental yield did not differ significantly according to hydrops severity. The most common genetic disorders identified were RASopathies, occurring in 30.3% (27/89) of cases with a causative pathogenic variant, most frequently due to a PTPN11 variant (44.4%; 12/27). The predominant inheritance pattern in causative pathogenic variants was autosomal dominant in monoallelic disease genes (57.3%; 51/89), with most being de novo (86.3%; 44/51). CONCLUSIONS: Use of prenatal next-generation sequencing in both isolated and non-isolated NIHF should be considered in the development of clinical pathways. Given the wide range of potential syndromic diagnoses and heterogeneity in the prenatal phenotype of NIHF, exome or whole-genome sequencing may prove to be a more appropriate testing approach than a targeted gene panel testing strategy. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Outcomes of pregnancies with more than one positive prenatal screening result in the first or second trimester.

OBJECTIVE: To describe adverse outcomes and fetal abnormalities in women with a positive prenatal screening result for more than one disorder. STUDY DESIGN: Study participants were drawn from a population of 452 901 women pregnant with singletons entering the California Prenatal Screening Program in their first-trimester. Risk assessment was provided for trisomy 21 and trisomy 18 in the first-trimester and trisomy 21, trisomy 18, neural tube defects, and Smith-Lemli-Opitz syndrome in the second-trimester. Inclusion in this study required positive screening for more than one of the screened conditions and a completed outcome of pregnancy survey. RESULTS: A total of 874 women met our study inclusion criteria. Over 25% of these pregnancies had a fetus with a chromosomal abnormality. Of the euploid pregnancies, 6.9% had a fetus with a major birth defect. Of the pregnancies with a fetus with neither a chromosomal abnormality nor a major birth defect, 9.3% ended in fetal demise. Overall, more than 50% of women with multiple positive screening results had either a fetus with a birth defect or a poor pregnancy outcome. CONCLUSION: Although it is rare to screen positive for more than one condition, such results indicate a very high risk for chromosomal abnormality, fetal demise, or structural abnormality.

Best ethical practices for clinicians and laboratories in the provision of noninvasive prenatal testing.

OBJECTIVE: The goal of this study is to provide an ethical framework for clinicians and companies providing noninvasive prenatal testing using cell-free fetal DNA or whole fetal cells. METHOD: In collaboration with a National Institutes of Health-supported research ethics consultation committee together with feedback from an interdisciplinary group of clinicians, members of industry, legal experts, and genetic counselors, we developed a set of best practices for the provision of noninvasive prenatal genetic testing. RESULTS: Principal recommendations include the amendment of current informed consent procedures to include attention to the noninvasive nature of new testing and the potential for a broader range of results earlier in the pregnancy. We strongly recommend that tests should only be provided through licensed medical providers and not directly to consumers. CONCLUSION: Prenatal tests, including new methods using cell-free fetal DNA, are not currently regulated by government agencies, and limited professional guidance is available. In the absence of regulation, companies and clinicians should cooperate to adopt responsible best ethical practices in the provision of these tests.

Risk of preterm birth among women using drugs during pregnancy with elevated α-fetoprotein.

OBJECTIVE: Examine the risk of preterm birth (PTB) among women who use drugs during pregnancy and have elevated α-fetoprotein (AFP). STUDY DESIGN: The sample included California singleton live births in 2005 to 2010 contained within a hospital discharge database linked to the Prenatal Screening Program. A selection of mothers who did not use drugs was selected at a ratio of 4:1. Risk of PTB was calculated using adjusted odds ratios and 95% confidence intervals (CIs) for women who did or did not use drugs by their AFP percentile. RESULTS: We identified 7190 women who used drugs and selected 28 760 women who did not. Of women using cocaine with AFP ⩾95th percentile, 43.8% delivered prematurely. Women using drugs with AFP ⩾95th percentile were 11 to 35 times as likely to deliver <32 weeks. CONCLUSION: The combination of drug use and elevated AFP results in high rates of PTB. This combination results in an additive risk.

The clinical significance of predictions based on screening second trimester mean arterial pressure: adverse maternal [corrected] and infant outcomes.

The design of a trial of primary prevention of hypertension in pregnancy rests on both the ability to identify women who are at risk and the definition of a clinically important outcome. The risk of developing antepartum hypertension can now be assessed nonivasively by the midpoint of pregnancy. However, maternal hypertension is not always associated with a clinically important adverse outcome for either mother or infant. The purpose of this study was to prospectively assess whether increasing risk of antepartum hypertension is associated with increasing rates of clinically important maternal and/or infant morbidity. We assembled a prospective cohort of 720 women with singleton pregnancies. The proportion of pregnancies complicated by both antepartum hypertension and maternal and/or infant morbidity increased significantly between low, moderate, and high risk groups (0.2, 6 and 58.8%, respectively, p less than 0.0001). We conclude that a trial of primary prevention of hypertension in pregnancy should include a measure of significant morbidity in mother and infant.

Predicting the risk of cystic fibrosis with echogenic fetal bowel and one cystic fibrosis mutation.

OBJECTIVE: To assess fetal risk for cystic fibrosis when echogenic bowel and one cystic fibrosis mutation are detected. METHODS: A hypothetical cohort of 1000 women with singleton pregnancies and echogenic fetal bowel during the second trimester was used to determine the probability of cystic fibrosis when one cystic fibrosis transmembrane conductance regulator mutation was detected. The risk of cystic fibrosis was calculated using the range of prevalence of cystic fibrosis in fetuses with echogenic bowel reported in the literature. Risk calculations for fetuses of Ashkenazi Jewish, Northern European, African-American, Hispanic, and Asian descent accounted for carrier frequencies and mutation detection rates specific to each ethnic group. RESULTS: As the assumed prevalence of cystic fibrosis increases from 1-25%, the probability that a white fetus with one mutation and echogenic fetal bowel actually has cystic fibrosis increases from 4.8% to 62.5%. Assuming a 2% risk of cystic fibrosis with echogenic fetal bowel, an Ashkenazi Jewish fetus and an Asian fetus with echogenic bowel and one mutation have a 3.1% and 72% risk of cystic fibrosis, respectively. The probability of cystic fibrosis in a nonwhite fetus is between those two extremes. CONCLUSION: The probability of cystic fibrosis after detection of echogenic bowel and one cystic fibrosis mutation varied among ethnic groups. Even at the highest prevalence of cystic fibrosis, most white fetuses will not have cystic fibrosis. In nonwhite populations almost half of these fetuses will have cystic fibrosis, even at the lowest prevalence of cystic fibrosis.

Cost-effectiveness of strategies used in the evaluation of pregnancies complicated by elevated maternal serum alpha-fetoprotein levels.

OBJECTIVE: To perform a cost-effectiveness analysis of various protocols used in the diagnostic evaluation of pregnancies complicated by elevated levels of maternal serum alpha-fetoprotein (MSAFP). METHODS: The variables incorporated in this model were the prevalence of relevant fetal anomalies; the sensitivity and specificity of MSAFP at 2.0 or 2.5 multiples of the median (MoM); and the sensitivity, specificity, cost, and safety of targeted ultrasound and amniocentesis. We expressed the cost-effectiveness of each strategy as the total cost of the diagnostic evaluation divided by the number of anomalous fetuses identified, yielding the cost per identified anomalous fetus. RESULTS: In a hypothetical cohort of 100,000 singleton pregnancies, a strategy of targeted ultrasound for MSAFP of at least 2.0 MoM detected 90 of 110 structurally abnormal fetuses, without iatrogenic fetal loss, at a cost of $5700 per anomalous fetus. A strategy of amniocentesis with karyo-type determination for MSAFP of at least 2.5 MoM detected 15 additional abnormal fetuses (87 structural abnormalities, ten autosomal aneuploidies, and eight sex chromosomal aneuploidies), with nine iatrogenic fetal losses, at an incremental cost of $46,100 per anomalous fetus. CONCLUSION: The increased cost and iatrogenic fetal loss rate may not justify the increased diagnostic yield of amniocentesis as compared with ultrasound in the evaluation of pregnancies complicated by elevated MSAFP.

Early prediction of antepartum hypertension.

We validated a mid-pregnancy screening mean arterial pressure (MAP2) of 85 mmHg or higher as a significant predictor of hypertension in pregnancy. During the 17-month period from October 1984 through February 1986, 730 women, or 16% of all women cared for and delivered at our institution, were screened at or near 20 weeks of amenorrhea. Of the 139 women with a MAP2 of 85 mmHg or higher, 21.6% developed antepartum hypertension, compared with only 0.7% of the 591 women with a MAP2 below 85 mmHg. The screening MAP2 level of 85 mmHg was the optimal cutoff for MAP2 as a screening test. Controlling for the value of the screening MAP2, the only other important predictors of antepartum hypertension were chronic hypertension and diabetes mellitus. Using these three variables, the probability that an individual pregnant woman will develop antepartum hypertension can be assessed with a high degree of accuracy (84.5%) by 20 weeks of amenorrhea. This assessment is noninvasive and simple to use. Three distinct levels of risk have been defined; the moderate- and high-risk groups warrant careful surveillance during pregnancy and may be reasonable groups in which to test preventive interventions.

Cystic fibrosis and chromosome abnormalities associated with echogenic fetal bowel.

OBJECTIVE: To determine the prevalence of cystic fibrosis mutations and chromosome abnormalities in the fetuses of a heterogeneous population of pregnant women referred for prenatal testing for echogenic fetal bowel. METHODS: Fetal or parental samples obtained after a second-trimester sonographic finding of echogenic fetal bowel were submitted to a referral diagnostic laboratory during a 2-year period. Results of DNA testing and karyotyping on these samples were analyzed to determine the prevalence of cystic fibrosis transmembrane reductase gene mutations and chromosome abnormalities. RESULTS: Of 244 cases tested, two fetuses were positive for two cystic fibrosis mutations. This rate (0.8% or two of 244) is 20 times higher than the general white population rate of one per 2500. In a third case, both parents were carriers but the fetus was not tested. Nine (8%) of 113 fetuses tested had one cystic fibrosis mutation. Of 106 fetuses for whom chromosome results were available, three (2.8%) fetuses had a chromosomal abnormality: two had trisomy 21 and one had Klinefelter syndrome. A fourth fetus carried a de novo, apparently balanced, 5;12 translocation. CONCLUSION: These laboratory results are representative of a broad spectrum of clinical settings and indicate a generalized increased risk associated with this sonographic finding. Therefore, when a second-trimester sonographic diagnosis of fetal echogenic bowel is made, fetal testing for both cystic fibrosis and chromosome abnormalities is warranted.

Ovulation induction with pulsatile gonadotropin-releasing hormone: a study of the subcutaneous route of administration.

The efficacy of ovulation induction with the use of intermittent gonadotropin-releasing hormone (GnRH) therapy was examined in seven infertile women with hypothalamic amenorrhea. GnRH was administered every 90 minutes via the subcutaneous route in doses ranging from 50 to 300 ng/kg. Analysis of the induced gonadotropin pulse pattern revealed normal to modestly increased luteinizing hormone secretory parameters (e.g., pulse amplitude) in six of the seven patients. Six of seven women and 15 of 16 treatment cycles (94%) were ovulatory. The conception rate was 43% per woman and 19% per cycle. However, detailed hormonal analysis of 13 treatment cycles revealed that only 1 cycle was entirely normal in terms of duration and/or steroid secretion.

Nonimmune hydrops fetalis.

In summary, NIHF is a heterogenous disorder resulting from a vast number of underlying pathologies. A thorough evaluation should be performed in all cases to attempt to establish the etiology. This requires a systematic approach that should logically proceed from least to most invasive testing. Despite increasing availability of treatment for some causes of NIHF, the prognosis for this condition in general remains poor. In cases of fetal or neonatal demise, autopsy should be encouraged to aid in confirming or making a diagnosis. It is especially important to rule out potentially treatable conditions, as well as genetic disorders with a risk of recurrence in future pregnancies.

Biochemical and ultrasound screening for chromosomal abnormalities.

The utility of ultrasound screening for Down syndrome should be judged by whether the pertinent markers are reliably obtained and by whether they efficiently discriminate between fetuses with Down syndrome and euploid fetuses. Furthermore, the markers must be reliable at a gestational age early enough to be clinically useful. Screening for characteristic congenital malformations will result in a low detection rate of Down syndrome, and many of these cases will be identified only after 24 weeks of gestation. The subtlety of many of the ultrasound findings of Down syndrome in the second trimester requires significant technical expertise if ultrasonographic screening is to be used. Investigation thus far has centered on identifying patients at increased risk of Down syndrome, and no data are available on how much a normal ultrasound might decrease the risk associated with advanced maternal age or abnormal biochemical screening. Biochemical screening is currently able to detect at least 60% of Down syndrome in a low-risk population. The ultimate value of ultrasound may be to help further define the risk assigned by age and biochemical screening, to provide each patient with an aggregate risk. The decision on whether or not to offer an amniocentesis could then be based on the findings of these various examinations, with the goal to improve the accuracy of age or biochemical screening alone. It remains for studies to be done to determine whether ultrasound can in fact decrease the prior risk, and for large enough series and formulas to be published that allow us to specifically define how to integrate the information from each screen.

Changes in functional status during pregnancy.

Changes in self-reported functional status during pregnancy were studied in 100 women. The baseline interview at 20 weeks was used for assessing subsequent change in maximal physical, mental, and emotional function as well as in global function and global sense of health. Although the transition instruments were only tested at three points during pregnancy (30, 35, and 40 weeks), they succeeded in detecting changes. In particular, both maximal physical function and global function tended to deteriorate as pregnancy progressed toward term, although few women considered themselves to be sick. The authors suggest that changes in functional status should be considered an important "outcome" of pregnancy. Patient-specific measures of change in self-reported maximal function might be used in future trials to help assess the impact of interventions on individual patient's maximal function. The timing of the baseline interview and frequency of the transition assessments should depend on the specific clinical problem under study.

Behçet's syndrome associated with intrauterine growth restriction: a case report and review of the literature.

BACKGROUND: Behçet's syndrome is an immune-mediated connective tissue disorder, and its primary manifestations are oral and genital ulcerations. To our knowledge no cases of adverse fetal outcome have been reported in pregnancies complicated by this disease. CASE: A 27-year-old primigravid woman with a diagnosis of Behçet's disease came to our institution during the first trimester. Her pregnancy was complicated by several exacerbations of her disease including vaginal and oral ulcerations and abdominal pain. She was treated with steroids throughout her pregnancy. She had ruptured membranes and evidence of fetal distress at 361/2 weeks and subsequently delivered a severely growth-restricted fetus (< 3rd percentile). CONCLUSION: Pregnancies complicated by Behçet's disease should be monitored closely for evidence of intrauterine growth restriction and fetal compromise, as are pregnancies complicated by similar connective tissue disorders.

Molecular zygosity studies aid in the management of discordant multiple gestations.

OBJECTIVE: Management of multiple gestations often requires identification of chorionicity. Sonographic evidence of dichorionicity can be present or inconclusive. DNA determination of zygosity can aid in the subsequent management of twins who are discordant for growth or anomalies. STUDY DESIGN: We present four cases in which monochorionicity could not be excluded sonographically. DNA zygosity studies were performed on amniocytes to guide management of the pregnancies. RESULTS: In two cases, one twin was affected with a significant anomaly. DNA zygosity studies provided a greater than 99% likelihood of monozygous twins in both cases. This altered the counseling regarding selective termination options. The other two cases involved severe intrauterine growth restriction and oligohydramnios in one twin, with a normal co-twin. The small twin appeared nonviable, and DNA studies were used to assess risk to the normal twin in the event of the co-twin's demise. We recommended delivery in the event of monozygous twinning and expectant management if the twins were dizygous. CONCLUSION: Diagnosis of chorionicity is important in multiple gestations. When chorionicity is unclear and management decisions would be altered by determination of zygosity, DNA studies should be considered.

Congenital heart defects in a large, unselected cohort of monochorionic twins.

OBJECTIVE: To determine the prevalence of congenital heart defects (CHDs) in a large, unselected cohort of monochorionic (MC) twins. STUDY DESIGN: We completed a chart review of all MC twin pregnancies in the Kaiser Permanente Northern California population from 1996 to 2003. CHDs were identified by diagnostic codes and confirmed by postnatal echocardiograms. Follow-up was obtained through one year of age. RESULT: A total of 926 liveborn MC twins met inclusion criteria. The prevalence of CHDs was 7.5%, 11.6 times the general population rate (CI 9.2 to 14.5). Septal defects were most common. 20% of infants with heart defects had twin-to-twin transfusion syndrome (TTTS) versus 8% of infants without defects (P<0.01); this association remained significant when controlling for potential confounders. CONCLUSION: The prevalence of CHDs in this large cohort of MC twins was significantly higher than the general population rate, with TTTS an added risk factor.

Transdisciplinary translational science and the case of preterm birth.

Medical researchers have called for new forms of translational science that can solve complex medical problems. Mainstream science has made complementary calls for heterogeneous teams of collaborators who conduct transdisciplinary research so as to solve complex social problems. Is transdisciplinary translational science what the medical community needs? What challenges must the medical community overcome to successfully implement this new form of translational science? This article makes several contributions. First, it clarifies the concept of transdisciplinary research and distinguishes it from other forms of collaboration. Second, it presents an example of a complex medical problem and a concrete effort to solve it through transdisciplinary collaboration: for example, the problem of preterm birth and the March of Dimes effort to form a transdisciplinary research center that synthesizes knowledge on it. The presentation of this example grounds discussion on new medical research models and reveals potential means by which they can be judged and evaluated. Third, this article identifies the challenges to forming transdisciplines and the practices that overcome them. Departments, universities and disciplines tend to form intellectual silos and adopt reductionist approaches. Forming a more integrated (or 'constructionist'), problem-based science reflective of transdisciplinary research requires the adoption of novel practices to overcome these obstacles.