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Non-Invasive Prenatal Screening (NIPS) is a useful screening method for common aneuploidies that can occur in pregnancies. It yields high sensitivities and specificities for the targeted conditions it tests for. Most commonly, these include Trisomies in chromosomes 21, 18, and 13, as well as aneuploidies in chromosomes X and Y. It does not, however, replace diagnostic testing. We review four cases seen by our institutions of patients who had NIPS performed with low-risk results and subsequently had fetuses affected with trisomy 18.All fetal samples were evaluated by level II anatomic ultrasound and tested on amniocytes or products of conception through karyotype or chromosomal microarray following low-risk NIPS.None of the fetuses showed evidence of mosaicism and had features (both on ultrasound and postnatally) consistent with Trisomy 18. Postnatal fluorescence in situ hybridization performed on Formalin-Fixed Paraffin-Embedded tissue from 3 of the affected pregnancies' placentas identified mosaicism of trisomy 18.We discuss the possible explanations for the discrepancy between NIPS results and fetal karyotype, including, but not limited to placental mosaicism, placental size, and limitations of NIPS as a screening test.

Objective The aim of this study was to survey the opinions of expectant parents regarding prenatal whole-exome sequencing. Methods The study used a questionnaire that focused on acceptability of prenatal whole-exome sequencing to individuals who pursued first-trimester prenatal screening in a tertiary academic medical center. A total of 186 expectant individuals completed the questionnaire. The results of the questionnaire were analyzed using descriptive statistics and logistic regression models. Results Eighty-three percent of the participants answered that prenatal whole-exome sequencing should be offered, 14.8% were neutral, and only 2.2% disagreed. Fifty-four percent of the participants were interested in having prenatal whole-exome sequencing for their fetus, 40.1% were neutral, and 6.6% disagreed. The majority of participants expressed a desire to know about treatable (96.2%) and non-treatable (86.3%) childhood conditions, and most said the same for treatable (76.0%) and non-treatable (74.3%) adult-onset conditions. Over half of the participants (59.7%) indicated a maximum acceptable turnaround time of 3 weeks or less for prenatal whole-exome sequencing. Conclusions The majority of respondents felt prenatal whole-exome sequencing should be offered. Moreover, the majority wanted to know prenatally about treatable and non-treatable childhood and adult conditions. © 2015 John Wiley & Sons, Ltd.

Objective We theorized that a significant number of women would choose integrated screening (IS) over first trimester screening (FTS) and that demographic characteristics and baseline anxiety levels might predict which patients would choose each test. We also hypothesized that screening results might alter patients' future preferences. Method Patients underwent non-directive genetic counselling and were offered FTS or IS. Prior to undergoing nuchal translucency (NT) ultrasound, patients were given surveys. These questionnaires were repeated in the second trimester and postpartum. They focussed on the patients' background, motivations for screening and anxiety level. Results Out of 110 patients surveyed, 81 returned their initial questionnaire. 60% of these patients chose FTS and 40% chose IS. There were no demographic differences between the groups. FTS patients desired early reassurance while IS patients wanted the 'most information' and the lowest chance of needing diagnostic testing. In all, 47 women returned second trimester questionnaires and 35 women returned postpartum surveys. These surveys demonstrated that women's motivations remained constant over time. Of the five screen positive results, only one woman regretted her screening choice. Conclusion One cannot predict patients' screening preferences, thus both FTS and IS should be offered. Given non-directive counselling, patients are generally satisfied with their screening choices.

The aim of this study was to determine whether pregnancies affected by fetal trisomy 13 are associated with second-trimester maternal serum analyte levels different from those typical of the unaffected population. Pregnancies with trisomy 13 were identified through cytogenetics laboratories. Those which had second-trimester maternal serum screening analyte measurements were further evaluated. Maternal serum analyte levels for each case and five matched controls were statistically analysed by matched ranked-sum analysis. 28 cases of fetal trisomy 13 were identified. The median AFP, uE3 and hCG levels were 1.35 MoM, 0.71 MoM and 0.90 MoM, respectively. Only uE3 levels were statistically different (p < 0.01) from those for the unaffected population. These data suggest that second-trimester maternal serum AFP, uE3 and hCG levels are not useful in detecting fetal trisomy 13 and protocols already existing for Down syndrome or trisomy 18 screening will not detect the majority of cases of this aneuploidy.

Placental proteins, such as inhibin A and hCG and its subunits, as well as the placental steroid progesterone, are elevated in second-trimester maternal serum from cases of fetal Down syndrome. Since different cellular mechanisms are required for protein versus steroid synthesis and secretion, these data suggest that a generalized placental hypersecretory phenomenon is associated with Down syndrome. Inhibin A and hCG are also elevated in cases of Turner syndrome with hydrops, and are reduced in cases of Turner syndrome without hydrops and in trisomy 18. The objective of the present study was to determine maternal serum levels of the placental steroid progesterone in cases of Turner syndrome and trisomy 18. Twenty-one cases of trisomy 18, 10 cases of Turner syndrome without hydrops and 12 cases of Turner syndrome with hydrops were identified and each matched to five control samples. Maternal serum progesterone levels were significantly elevated in Turner syndrome with hydrops (2.11 MoM), slightly reduced in Turner syndrome without hydrops (0.90 MoM) and modestly, though significantly, reduced in trisomy 18 (0.73 MoM). These data are similar to the patterns seen for inhibin A and hCG, suggesting that the overall synthetic and/or secretory activity of the placenta is increased in Turner syndrome with hydrops and decreased in Turner syndrome without hydrops and in trisomy 18. These data may be helpful in understanding the pathophysiological basis of serum marker patterns in these aneuploidies.

The objective was to investigate whether cases of fetal trisomy 18 and Turner syndrome with and without hydrops were associated with alterations in the second-trimester levels of maternal serum inhibin A. Twenty-one cases of trisomy 18, 10 cases of Turner syndrome without hydrops and 12 cases of Turner syndrome with hydrops were identified. Five control samples were matched to each case for date of sample collection and completed week of gestation. Inhibin A levels were modestly, but significantly reduced in cases of trisomy 18 (median = 0.88 MoM) and Turner syndrome without hydrops (median = 0.64 MoM). In contrast, inhibin A levels were markedly increased in cases of Turner syndrome with hydrops (median = 3.91 MoM). These data for Turner syndrome are similar to those for human chorionic gonadotropin (hCG). The addition of inhibin A to multiple marker screening (alpha-fetoprotein, unconjugated oestriol and hCG) resulted in a median increase in the Down syndrome risk of 2.6-fold in cases of Turner syndrome with hydrops. The addition of inhibin A to multiple marker Down syndrome screening programmes will be likely to enhance the detection of fetal Turner syndrome with hydrops, but will not contribute substantially to the detection of fetal trisomy 18.

Levels of beta-core fragment and total oestriol in second-trimester maternal urine samples were measured in 32 Down syndrome pregnancies and 206 control pregnancies. Beta-core fragment and total oestriol values were corrected for the urinary creatinine level and expressed as multiples of the control medians (MOM). In addition, the ratio of the beta-core fragment level to the total oestriol level, without creatinine correction, was calculated, and expressed as MOM values. The median beta-core fragment, total oestriol, and ratio levels in Down syndrome cases were 5.42, 0.64, and 9.32 MOM, respectively. In the Down syndrome pregnancies, 66 per cent of the beta-core fragment levels were above the 95th centile of control levels, while 22 per cent of the total oestriol levels were below the fifth centile of control levels. In combination with maternal age, measurement of beta-core fragment and total oestriol levels in Down syndrome pregnancy resulted in an 80 per cent detection rate at a 5 per cent false-positive rate. Use of the ratio resulted in a univariate detection rate of 72 per cent. In combination with maternal age, the ratio resulted in a detection rate of 81 per cent at a 5 per cent false-positive rate. Based on this unmatched study, the measurement of a ratio of beta-core fragment to total oestriol levels, without the need for creatinine correction, may be useful in screening for fetal Down syndrome in second-trimester urine.

Associations between elevated amniotic fluid glucose and insulin levels in the second trimester and the subsequent development of gestational diabetes have been reported. We conducted a case-control study to determine which analyte best predicts future maternal glucose intolerance. Thirty-nine women diagnosed with gestational diabetes (criteria of Carpenter and Coustan, Am. J. Obstet. Gynecol., 144, 768, 1982) who had undergone genetic amniocentesis for advanced maternal age were matched with euglycaemic controls. Glucose and insulin concentrations were determined by analysis of stored amniotic fluid samples. No significant difference was detected between cases and controls for amniotic fluid glucose concentrations. Amniotic fluid insulin concentrations were significantly higher in cases (mean rank 4.44, P < 0.01, using matched rank analysis of variance, where 1 is the lowest and 6 is the highest rank). After conversion to multiples of the median, 20 per cent of women with subsequent gestational diabetes were found to have amniotic fluid glucose levels at or above the 90th centile, while 35 per cent of cases had similarly elevated amniotic fluid insulin levels. We conclude that second-trimester amniotic fluid insulin is a more sensitive predictor of impending glucose intolerance than amniotic fluid glucose, although neither is sufficiently powerful to use alone as a screening test.

The objective was to investigate whether non-immune hydrops in euploid pregnancies is associated with alterations in the second-trimester levels of maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Ten singleton cases of fetal non-immune hydrops were identified. The aetiology and timing of onset of the earliest signs of non-immune hydrops, including polyhydramnios, in relation to maternal serum screening for Down syndrome were assessed. There was no clear relationship between the aetiology of non-immune hydrops and the analyte levels, as aetiologies varied widely. AFP levels were elevated overall (median = 1.78 MOM) and uE3 levels were unremarkable (median = 0.82 MOM). hCG levels were elevated (median = 3.53 MOM) when non-immune hydrops was present at the time of screening, but were unremarkable (median = 0.82 MOM) when the non-immune hydrops presented later. It is concluded that second-trimester non-immune hydrops is associated with elevated hCG levels.

Nine centres collaborated to examine the feasibility of a screening method for trisomy 18 that was based on assigning individual risk, using a combination of maternal age and measurements of alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Second-trimester measurements of these analytes were obtained from 94 trisomy 18 pregnancies. In the 89 pregnancies without an associated open defect, the median levels for AFP, uE3, and hCG were 0.65, 0.43 and 0.36 multiples of the unaffected population median, respectively. The strongest individual predictor of risk for trisomy 18 was uE3, followed by hCG, AFP, and maternal age, in that order. Using a method of individual risk estimation that is based on the three markers and maternal age, 60 per cent of pregnancies associated with trisomy 18 would be detected at a risk cut-off level of 1:100, with a false-positive rate of about 0.2 per cent. One in nine pregnancies identified as being at increased risk for trisomy 18 would be expected to have an affected pregnancy. This risk-based screening method is more efficient than an existing method that is based on fixed analyte cut-off levels. Even though the birth prevalence of trisomy 18 is low, prenatal screening can be justified when performed in conjunction with Down syndrome screening and when a high proportion of women offered amniocentesis have an affected fetus.

Urinary gonadotropin peptide (UGP; beta-core fragment), a major metabolite of human chorionic gonadotropin (hCG), was shown recently to be markedly elevated in Down syndrome pregnancy between 19 and 22 weeks of gestation. To confirm and extend this finding, we obtained maternal urine and matching maternal serum samples from 14 cases of Down syndrome and six other aneuploidies between 17 and 21 weeks of gestation. UGP was measured in all these samples and in 91 singleton control urines. Results were corrected for urinary creatinine level and expressed as multiples of the control median (MOM). hCG levels were assayed in all serum samples from the cases and compared with previously established reference values. The median UGP level in Down syndrome cases was 5.34 MOM (range 2.71-12.57); 88 per cent of the values were above the 95th centile of control levels after modelling. The median maternal serum hCG level for the same cases was 2.20 MOM (range 0.84-3.40); 36 per cent of the values were above the 95th centile. The level of UGP in every case including all other aneuploidies was higher than the comparable maternal serum hCG level. Elevated UGP measurements are strongly associated with fetal Down syndrome during the second trimester and could contribute to improved Down syndrome screening protocols that are more accessible and less expensive than are currently available.

Objective To contrast Spanish-speaking (S) with English-speaking (E) obstetric patients regarding utilization of genetic screening, motivation for undergoing/declining screening, pregnancy-related anxiety, knowledge about genetic conditions, and printed information as an adjunct to counseling. Method Paper surveys were given to patients (n = 121) in an academic OB/GYN clinic or placed in charts (n = 271) over a 4-week period. Comparisons were evaluated with Chi-square and Fisher's exact tests. Results Completed surveys were returned from 245 gravidas (response rate 63%, S 48%, and E 67%). Uptake of genetic screening was similar between the groups (S 69% vs E 57%, p = 0.13). No significant differences were noted in patients' motivation regarding screening, source of screening information, or self-assessed pregnancy-related anxiety. Familiarity of genetic disorders other than Down syndrome differed between the S and E groups (p < 0.003). Perceived positive utility of printed information differed significantly when groups were analyzed by language (S 85% vs E 47%, p < 0.001) and by uptake of screening(screened 62% vs not screened 44%, p = 0.006). Conclusion A majority of study participants (n = 147, 60%) chose genetic screening; uptake and motivation were similar across language groups. Familiarity with genetic conditions was deficient and screening terminology confusing regardless of primary language. The perceived positive utility of printed information (S > E) highlights the importance of clear and early counseling. Copyright © 2011 John Wiley & Sons, Ltd.

Hydrops fetalis and fetal death caused by fetal parvovirus B19 infection have been reported to be associated with elevated maternal serum alpha-fetoprotein (AFP), based on a total of six cases. It has been suggested that the absence of AFP elevation may be reassuring. Maternal serum levels of the Down syndrome screening markers unconjugated oestriol and human chorionic gonadotropin in cases of fetal parvovirus infection have not been previously reported. We report four cases of hydrops fetalis and fetal death caused by fetal parvovirus infection, each with unremarkable second-trimester levels of AFP, unconjugated oestriol, and human chorionic gonadotropin.

Two prenatal centres in New England, routinely using a screening protocol for fetal Down syndrome that included maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG) measurements in combination with maternal age, adopted a separate screening protocol for trisomy 18. That protocol identified a pregnancy as being at high risk when AFP, uE3, and hCG measurements all fell at or below specified cut-offs (0.75, 0.60, and 0.55 multiples of the median, respectively), regardless of maternal age. Among the first 19,491 women screened, 98 (0.5 per cent) were found to have values which placed them in the high-risk category. Four of these women were subsequently found not to be pregnant. In two others, samples from non-pregnant individuals were found to have been incorrectly submitted for analysis in place of the samples from the pregnant women. All of the remaining 92 women were counselled and offered amniocentesis and fetal karyotyping. Eighty-eight (96 per cent) accepted. Karyotypes or birth outcomes were available on all 92 pregnancies. Six cases of trisomy 18 and one case of Turner syndrome were identified by karyotype. One case of trisomy 18 was identified for every 14 unaffected pregnancies offered amniocentesis. In the present prospective study, an estimated 85 per cent of the cases of trisomy 18 were identified. However, given the small number of cases (six), the 95 per cent confidence interval for the detection rate is broad (40-95 per cent).

We theorized that a significant number of women would choose integrated screening (IS) over first trimester screening (FTS) and that demographic characteristics and baseline anxiety levels might predict which patients would choose each test. We also hypothesized that screening results might alter patients' future preferences.Patients underwent non-directive genetic counselling and were offered FTS or IS. Prior to undergoing nuchal translucency (NT) ultrasound, patients were given surveys. These questionnaires were repeated in the second trimester and postpartum. They focussed on the patients' background, motivations for screening and anxiety level.Out of 110 patients surveyed, 81 returned their initial questionnaire. 60% of these patients chose FTS and 40% chose IS. There were no demographic differences between the groups. FTS patients desired early reassurance while IS patients wanted the 'most information' and the lowest chance of needing diagnostic testing. In all, 47 women returned second trimester questionnaires and 35 women returned postpartum surveys. These surveys demonstrated that women's motivations remained constant over time. Of the five screen positive results, only one woman regretted her screening choice.One cannot predict patients' screening preferences, thus both FTS and IS should be offered. Given non-directive counselling, patients are generally satisfied with their screening choices.

The aim of this study was to determine whether pregnancies affected by fetal trisomy 13 are associated with second-trimester maternal serum analyte levels different from those typical of the unaffected population. Pregnancies with trisomy 13 were identified through cytogenetics laboratories. Those which had second-trimester maternal serum screening analyte measurements were further evaluated. Maternal serum analyte levels for each case and five matched controls were statistically analysed by matched ranked-sum analysis. 28 cases of fetal trisomy 13 were identified. The median AFP, uE3 and hCG levels were 1.35 MoM, 0.71 MoM and 0.90 MoM, respectively. Only uE3 levels were statistically different (p0.01) from those for the unaffected population. These data suggest that second-trimester maternal serum AFP, uE3 and hCG levels are not useful in detecting fetal trisomy 13 and protocols already existing for Down syndrome or trisomy 18 screening will not detect the majority of cases of this aneuploidy.

Placental proteins, such as inhibin A and hCG and its subunits, as well as the placental steroid progesterone, are elevated in second-trimester maternal serum from cases of fetal Down syndrome. Since different cellular mechanisms are required for protein versus steroid synthesis and secretion, these data suggest that a generalized placental hypersecretory phenomenon is associated with Down syndrome. Inhibin A and hCG are also elevated in cases of Turner syndrome with hydrops, and are reduced in cases of Turner syndrome without hydrops and in trisomy 18. The objective of the present study was to determine maternal serum levels of the placental steroid progesterone in cases of Turner syndrome and trisomy 18. Twenty-one cases of trisomy 18, 10 cases of Turner syndrome without hydrops and 12 cases of Turner syndrome with hydrops were identified and each matched to five control samples. Maternal serum progesterone levels were significantly elevated in Turner syndrome with hydrops (2.11 MoM), slightly reduced in Turner syndrome without hydrops (0.90 MoM) and modestly, though significantly, reduced in trisomy 18 (0.73 MoM). These data are similar to the patterns seen for inhibin A and hCG, suggesting that the overall synthetic and/or secretory activity of the placenta is increased in Turner syndrome with hydrops and decreased in Turner syndrome without hydrops and in trisomy 18. These data may be helpful in understanding the pathophysiological basis of serum marker patterns in these aneuploidies.

The objective was to investigate whether cases of fetal trisomy 18 and Turner syndrome with and without hydrops were associated with alterations in the second-trimester levels of maternal serum inhibin A. Twenty-one cases of trisomy 18, 10 cases of Turner syndrome without hydrops and 12 cases of Turner syndrome with hydrops were identified. Five control samples were matched to each case for date of sample collection and completed week of gestation. Inhibin A levels were modestly, but significantly reduced in cases of trisomy 18 (median = 0.88 MoM) and Turner syndrome without hydrops (median = 0.64 MoM). In contrast, inhibin A levels were markedly increased in cases of Turner syndrome with hydrops (median = 3.91 MoM). These data for Turner syndrome are similar to those for human chorionic gonadotropin (hCG). The addition of inhibin A to multiple marker screening (alpha-fetoprotein, unconjugated oestriol and hCG) resulted in a median increase in the Down syndrome risk of 2.6-fold in cases of Turner syndrome with hydrops. The addition of inhibin A to multiple marker Down syndrome screening programmes will be likely to enhance the detection of fetal Turner syndrome with hydrops, but will not contribute substantially to the detection of fetal trisomy 18.

Levels of beta-core fragment and total oestriol in second-trimester maternal urine samples were measured in 32 Down syndrome pregnancies and 206 control pregnancies. Beta-core fragment and total oestriol values were corrected for the urinary creatinine level and expressed as multiples of the control medians (MOM). In addition, the ratio of the beta-core fragment level to the total oestriol level, without creatinine correction, was calculated, and expressed as MOM values. The median beta-core fragment, total oestriol, and ratio levels in Down syndrome cases were 5.42, 0.64, and 9.32 MOM, respectively. In the Down syndrome pregnancies, 66 per cent of the beta-core fragment levels were above the 95th centile of control levels, while 22 per cent of the total oestriol levels were below the fifth centile of control levels. In combination with maternal age, measurement of beta-core fragment and total oestriol levels in Down syndrome pregnancy resulted in an 80 per cent detection rate at a 5 per cent false-positive rate. Use of the ratio resulted in a univariate detection rate of 72 per cent. In combination with maternal age, the ratio resulted in a detection rate of 81 per cent at a 5 per cent false-positive rate. Based on this unmatched study, the measurement of a ratio of beta-core fragment to total oestriol levels, without the need for creatinine correction, may be useful in screening for fetal Down syndrome in second-trimester urine.

Associations between elevated amniotic fluid glucose and insulin levels in the second trimester and the subsequent development of gestational diabetes have been reported. We conducted a case-control study to determine which analyte best predicts future maternal glucose intolerance. Thirty-nine women diagnosed with gestational diabetes (criteria of Carpenter and Coustan, Am. J. Obstet. Gynecol., 144, 768, 1982) who had undergone genetic amniocentesis for advanced maternal age were matched with euglycaemic controls. Glucose and insulin concentrations were determined by analysis of stored amniotic fluid samples. No significant difference was detected between cases and controls for amniotic fluid glucose concentrations. Amniotic fluid insulin concentrations were significantly higher in cases (mean rank 4.44, P0.01, using matched rank analysis of variance, where 1 is the lowest and 6 is the highest rank). After conversion to multiples of the median, 20 per cent of women with subsequent gestational diabetes were found to have amniotic fluid glucose levels at or above the 90th centile, while 35 per cent of cases had similarly elevated amniotic fluid insulin levels. We conclude that second-trimester amniotic fluid insulin is a more sensitive predictor of impending glucose intolerance than amniotic fluid glucose, although neither is sufficiently powerful to use alone as a screening test.

The objective was to investigate whether non-immune hydrops in euploid pregnancies is associated with alterations in the second-trimester levels of maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Ten singleton cases of fetal non-immune hydrops were identified. The aetiology and timing of onset of the earliest signs of non-immune hydrops, including polyhydramnios, in relation to maternal serum screening for Down syndrome were assessed. There was no clear relationship between the aetiology of non-immune hydrops and the analyte levels, as aetiologies varied widely. AFP levels were elevated overall (median = 1.78 MOM) and uE3 levels were unremarkable (median = 0.82 MOM). hCG levels were elevated (median = 3.53 MOM) when non-immune hydrops was present at the time of screening, but were unremarkable (median = 0.82 MOM) when the non-immune hydrops presented later. It is concluded that second-trimester non-immune hydrops is associated with elevated hCG levels.

The presence of a single umbilical artery is associated with fetal congenital malformations and cytogenetic abnormalities. The incidence of chromosomal abnormalities in perinatal deaths complicated by a single umbilical artery is unknown. We studied the proportion of cytogenetic abnormalities associated with a single umbilical artery among perinatal deaths undergoing autopsy. Of 1078 autopsies, 42 (3.9 per cent) were identified with a single umbilical artery. Chromosome analysis was attempted in 21 of the 42 cases (50 per cent). There were 16 successful chromosome analyses, of which three (18.75 per cent) were abnormal. All the chromosomally abnormal fetuses had major congenital malformations. These data suggest that in a perinatal death, the presence of a single umbilical artery does not clinically alter the a priori risk of cytogenetic abnormalities.