Prevalence of common aneuploidy in twin pregnancies.

The incidence of chromosomal abnormalities in twin pregnancies is not well-studied. In this retrospective study, we investigated the frequency of chromosomal abnormalities in twin pregnancies and compared the incidence of chromosomal abnormalities in dichorionic diamniotic (DD) and monochorionic diamniotic (MD) twins. We used data from 57 clinical facilities across Japan. Twin pregnancies of more than 12 weeks of gestation managed between January 2016 and December 2018 were included in the study. A total of 2899 and 1908 cases of DD and MD twins, respectively, were reported, and the incidence of chromosomal abnormalities in one or both fetuses was 0.9% (25/2899) and 0.2% (4/1908) in each group (p = 0.004). In this study, the most common chromosomal abnormality was trisomy 21 (51.7% [15/29]), followed by trisomy 18 (13.8% [4/29]) and trisomy 13 (6.9% [2/29]). The incidence of trisomy 21 in MD twins was lower than that in DD twins (0.05% vs. 0.5%, p = 0.007). Trisomy 21 was less common in MD twins, even when compared with the expected incidence in singletons (0.05% vs. 0.3%, RR 0.15 [95% CI 0.04-0.68]). The risk of chromosomal abnormality decreases in twin pregnancies, especially in MD twins.

What are the ethical issues involved in noninvasive prenatal testing in Japan?

AIMS: Noninvasive prenatal testing (NIPT) of pregnant women has been performed worldwide since 2011, and it is currently performed in more than 90 countries. However, the rate of adoption in Japan remains at less than 2%. This review seeks to identify the ethical and practical issues surrounding noninvasive prenatal screening-including the purpose of the test, its pros and cons, issues surrounding fair treatment, and social factors-to better understand why the adoption rate remains low. METHODS: This study examines the complex ethical issues surrounding noninvasive prenatal testing, including the purpose of the test, its pros and cons, issues related to fair treatment, and social factors. RESULTS: Although cell-free DNA analysis for common fetal trisomies using maternal blood is highly accurate, lack of access to such testing and discriminatory attitudes in society remain important barriers. Personal choices such as whether to undergo noninvasive prenatal screening and whether to continue a pregnancy are sometimes criticized by those who believe that it leads to the "selection of life" or discrimination against people with disabilities. CONCLUSIONS: Obstetrics has changed dramatically in recent years, and prenatal diagnosis technology has also advanced. To keep up with these advances, better information should be provided to ensure the public has a more nuanced understanding of the screening beyond the overused argument that it leads to "selection of life."

Relationship between delivery with anesthesia and postpartum depression: The Japan Environment and Children's Study (JECS).

BACKGROUND: Postpartum depression is one of the most commonly experienced psychological disorders for women after childbirth, usually occurring within one year. This study aimed to clarify whether women with delivery with anesthesia, including epidural analgesia, spinal-epidural analgesia, and paracervical block, had a decreased risk of postpartum depression after giving birth in Japan. METHODS: The Japan Environment and Children's Study (JECS) was a prospective cohort study that enrolled registered fetal records (n = 104,065) in 15 regions nationwide in Japan. Binomial logistic regression analyses were performed to calculate the adjusted odd ratios (aORs) for the association between mode of delivery with or without anesthesia and postpartum depression at one-, six- and twelve-months after childbirth. RESULTS: At six months after childbirth, vaginal delivery with anesthesia was associated with a higher risk of postpartum depression (aOR: 1.233, 95% confidence interval: 1.079-1.409), compared with vaginal delivery without analgesia. Nevertheless, the risk dropped off one year after delivery. Among the pregnant women who requested delivery with anesthesia, 5.1% had a positive Kessler-6 scale (K6) score for depression before the first trimester (p < 0.001), which was significantly higher than the proportions in the vaginal delivery without analgesia (3.5%). CONCLUSIONS: Our data suggested that the risk of postpartum depression at six months after childbirth tended to be increased after vaginal delivery with anesthesia, compared with vaginal delivery without analgesia. Requests for delivery with anesthesia continue to be relatively uncommon in Japan, and women who make such requests might be more likely to experience postpartum depressive symptoms because of underlying maternal environmental statuses.

Trends of fetal chromosome analysis by amniocentesis before and after beginning of noninvasive prenatal testing: A single-center experience in Japan.

AIM: This study is to investigate the role of amniocentesis for prenatal diagnosis before and after the beginning of noninvasive prenatal testing (NIPT) in Japan. METHODS: We performed a retrospective analysis of genetic amniocentesis at mid-trimester (15-20 gestational weeks) for fetal karyotype analysis at Nagoya City University between April 2006 and March 2020. The indications, test results, and the detection rate of fetal abnormal karyotype were compared before (phase 1, P1) and after (phase 2, P2) beginning of NIPT at April 2013. RESULTS: A total of 2458 (P1: 1132, P2: 1326) amniocentesis were enrolled in this study. The most frequent indication was advanced maternal age in both phases (P1: 78.2% %, P2: 81.1%). In P2, 110 patients (8.3%) received amniocentesis after positive or nonreportable NIPT results. Other indications were fetal abnormal findings by ultrasounds (P1: 15.4%, P2: 17.7%), abnormal maternal serum screening results (P1: 8.0%, P2: 10%), previous child with fetal chromosome aberration (P1: 6.5%, P2: 3.5%), and translocation of either partner (P1:1.5%, P2: 2.1%). The detection rate for fetal chromosomal aberrations including all indications was significantly increased in P2 (15.9%, 95% CI 14.0-18.0) as compared to P1 (9.0%, 7.4-10.8). However, if the indication was only advanced maternal age, the positive detection rate kept low in both phases (P1: 5.2%, 3.7-7.1, P2: 4.2%, 2.9-5.9). CONCLUSION: Since the initiation of NIPT, the detection rate of fetal chromosomal abnormalities was higher in this study, suggesting that amniocentesis cannot be strongly recommended for advanced maternal age alone.

Evaluation of the clinical performance of noninvasive prenatal testing at a Japanese laboratory.

AIM: We aimed to evaluate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of noninvasive prenatal testing (NIPT) in high-risk pregnant women. METHODS: Pregnant women who underwent GeneTech NIPT, the most commonly used NIPT in Japan, between January 2015 and March 2019, at Japan NIPT Consortium medical sites were recruited for this study. The exclusion criteria were as follows: pregnant women with missing survey items, multiple pregnancy/vanishing twins, chromosomal abnormalities in the fetus other than the NIPT target disease, and nonreportable NIPT results. Sensitivity and specificity were calculated from the obtained data, and maternal age-specific PPV and NPV were estimated. RESULTS: Of the 45 504 cases, 44 263 cases fulfilling the study criteria were included. The mean maternal age and gestational weeks at the time of procedure were 38.5 years and 13.1 weeks, respectively. Sensitivities were 99.78% (95% confidence interval [95% CI]: 98.78-99.96), 99.12% (95% CI: 96.83-99.76), and 100% (95% CI: 88.30-100) for trisomies 21, 18, and 13, respectively. Specificities were more than 99.9% for trisomies 21, 18, and 13, respectively. Maternal age-specific PPVs were more than 93%, 77%, and 43% at the age of 35 years for trisomies 21, 18, and 13, respectively. CONCLUSION: The GeneTech NIPT data showed high sensitivity and specificity in the detection of fetal trisomies 21, 18, and 13 in high-risk pregnant women, and maternal age-specific PPVs were obtained. These results could provide more accurate and improved information regarding NIPT for genetic counseling in Japan.

Qualitative investigation of the factors that generate ambivalent feelings in women who give birth after receiving negative results from non-invasive prenatal testing.

BACKGROUND: Women who receive negative results from non-invasive prenatal genetic testing (NIPT) may find that they later have mixed or ambivalent feelings, for example, feelings of accepting NIPT and regretting undergoing the test. This study aimed to investigate the factors generating ambivalent feelings among women who gave birth after having received negative results from NIPT. METHODS: A questionnaire was sent to women who received a negative NIPT result, and a contents analysis was conducted focusing on ambivalent expressions for those 1562 women who responded the questionnaire. The qualitative data gathered from the questionnaire were analyzed using the N-Vivo software package. RESULTS: Environmental factors, genetic counseling-related factors, and increased anticipatory anxiety, affected the feeling of ambivalence among pregnant women. Furthermore, pregnant women desired more information regarding the detailed prognosis for individuals with Down syndrome and living with them and/or termination, assuming the possibility that they were positive. CONCLUSIONS: Three major interrelated factors affected the feeling of ambivalence in women. Highlighting and discussing such factors during genetic counseling may resolve some of these ambivalences, thereby enhancing the quality of decisions made by pregnant women.

Effects of long working hours and shift work during pregnancy on obstetric and perinatal outcomes: A large prospective cohort study-Japan Environment and Children's Study.

BACKGROUND: The work patterns of pregnant women may be related to adverse obstetric and perinatal outcomes. This study aimed to clarify the effects of weekly working time according to frequencies of night shifts during pregnancy on adverse outcomes in Japan. METHODS: The Japan Environment and Children's Study, a prospective cohort study, was conducted in 15 regions nationwide in Japan. The study population included pregnant women with singleton pregnancies (n = 99 744). The mothers' working hours and frequencies of night shifts during the first and the second/third trimesters were assessed using a self-administered questionnaire. Outcome data were collected from medical transcripts. RESULTS: Compared with nonworking women, women who worked during pregnancy had significantly increased adjusted odds ratios (aORs) of threatened miscarriage (maximum aOR: 1.47, 95% confidence interval [95% CI]: 1.26-1.73) and of threatened preterm labor (maximum aOR: 1.63, 95% CI: 1.41-1.87). Increased aORs were observed for hypertensive disorders of pregnancy (maximum aOR: 2.02, 95% CI: 1.39-2.93) in women working ≥36 hours per week with night shifts, for vacuum/forceps delivery (maximum aOR: 1.34, 95% CI: 1.22-1.48) at ≥36 hours with or without night shifts, and for small-for-gestational-age babies (aOR: 1.32, 95% CI: 1.10-1.59) at ≥46 hours with night shifts. In contrast, lower aORs were observed for gestational diabetes and meconium-stained amniotic fluid in women working without night shifts. CONCLUSIONS: Work during pregnancy slightly increased the risks of threatened miscarriage and threatened preterm labor. Long working hours increased the risks of hypertensive disorders of pregnancy, vacuum/forceps delivery, and small-for-gestational-age babies.

Classification of factors involved in nonreportable results of noninvasive prenatal testing (NIPT) and prediction of success rate of second NIPT.

OBJECTIVE: To evaluate the reasons for nonreportable cell-free DNA (cfDNA) results in noninvasive prenatal testing (NIPT), we retrospectively studied maternal characteristics and other details associated with the results. METHODS: A multicenter retrospective cohort study in pregnant women undergoing NIPT by massively parallel sequencing (MPS) with failed cfDNA tests was performed between April 2013 and March 2017. The women's data and MPS results were analyzed in terms of maternal characteristics, test performance, fetal fraction (FF), z scores, anticoagulation therapy, and other details of the nonreportable cases. RESULTS: Overall, 110 (0.32%) of 34 626 pregnant women had nonreportable cfDNA test results after an initial blood sampling; 22 (20.0%) cases had a low FF (<4%), and 18 (16.4%) cases including those with a maternal malignancy, were found to have altered genomic profile. Approximately half of the cases with nonreportable results had borderline z score. Among the women with nonreportable results because of altered genomic profile, the success rate of retesting using a second blood sampling was relatively low (25.0%-33.3%). Thirteen (11.8%) of the women with nonreportable results had required hypodermic heparin injection. CONCLUSIONS: The classification of nonreportable results using cfDNA analysis is important to provide women with precise information and to reduce anxiety during pregnancy.

Maternal age-specific risk for trisomy 21 based on the clinical performance of NIPT and empirically derived NIPT age-specific positive and negative predictive values in Japan.

The data collected by nation-wide study of noninvasive prenatal genetic testing (NIPT) for trisomy 21 from 21,610 pregnant women with advanced maternal age in Japan were reported. Among 188 NIPT-positive cases, 180 cases were true positive. The incidence of aneuploidy according to maternal age was estimated using a state-space model. Although, the frequency of trisomy increased exponentially with maternal age as previously reported, the maternal age-specific risk for trisomy 21 that was based on the clinical performance of NIPT was lower than the predicted risk in previous Western cohorts based on the data from invasive prenatal testing (Bayesian two-sided tail-area probability P = 0.0156). The empirical positive predictive value (PPV) of NIPT is likely to turn out higher than that of the theoretical PPV calculated from the sensitivity/specificity of the test and the incidence of trisomy 21 from this study.

Correction: Maternal age-specific risk for trisomy 21 based on the clinical performance of NIPT and empirically derived NIPT age-specific positive and negative predictive values in Japan.

Since the advance online publication of this article, the authors of the above paper have noticed errors in the list of authors and affiliations. The article with correct author information now appears in this issue.

Performance and outcomes of noninvasive prenatal testing for twin pregnancies in Japan.

AIM: The purpose of this study was to describe the characteristics of women with twin pregnancies who undergo noninvasive prenatal testing (NIPT) as well as the post-partum and neonatal outcomes of such cases in Japan. METHODS: The study population consisted of women who were pregnant with twins and who underwent NIPT using massively parallel sequencing (MPS) at Nagoya City University Hospital between April 2013 and June 2016. Questionnaires were completed pre-NIPT and post-partum. RESULTS: Among 4009 women who underwent NIPT during the study period, 75 women (1.9%) were pregnant with twins. Fifteen women (20%) experienced vanishing twin/intrauterine fetal deaths at <22 weeks, and 60 women (80%) had normal twin pregnancies at the time of genetic counseling for NIPT. The use of NIPT was correlated with increased proportions of women using assisted reproductive technology (ART). The test had a high performance, with a false-positive rate of 1.7% and no false negatives. CONCLUSION: In this study, NIPT had a high performance, with a false positive rate of 1.7% and no false negatives. When treating women with twin pregnancies, the efficacy of NIPT should be explained during genetic counseling. Further larger studies are required to assess the reliability and validity of NIPT in twin pregnancies.

Psychological distress in post-partum women after non-invasive prenatal testing (NIPT) in Japan.

AIM: The purpose of this study was to clarify the characteristics of psychological mental distress in post-partum women after non-invasive prenatal testing (NIPT) in Japan. METHODS: Psychological mental distress was assessed using the Kessler Psychological Distress Scale (K6). We compared patients with (i) low pre-NIPT K6 and low post-partum K6 scores (control group), and (ii) low pre-NIPT K6 and a high post-partum K6 scores (case group). RESULTS: Among the 697 women who underwent NIPT, 29 (4.2%) had low pre-NIPT K6 and high post-partum K6 scores (case group) and 668 (95.8%) had low pre-NIPT K6 and low post-partum K6 scores (control). Among women with negative NIPT findings, post-partum women with a high K6 score were compared to a control group of women with a low K6 score. Logistic regression analysis showed that primiparity (P = 0.007), low birthweight (P = 0.005) and use of intracytoplasmic sperm injection (P = 0.02) and assisted reproductive technology (P = 0.05) were significantly different between the groups. CONCLUSION: Even if women do not feel mental distress before NIPT, they may develop mental stress post-partum. In particular, primipara women who conceived through assisted reproductive technology (especially intracytoplasmic sperm injection) and gave birth to a low birthweight baby were more susceptible to developing post-partum distress. Thus, it is important to educate women that support is available, with consultation with other healthcare professionals during genetic counseling if necessary. Further studies are needed in order to determine the factors associated with post-partum mental distress.

Current status of non-invasive prenatal testing in Japan.

AIM: The purpose of this study was to report the 3-year experience of a nationwide demonstration project to introduce non-invasive prenatal testing (NIPT) of maternal plasma for aneuploidy, and review the current status of NIPT in Japan. METHODS: Tests were conducted to detect aneuploidy in high-risk pregnant women, and adequate genetic counseling was provided. The clinical data, test results, and pregnancy outcomes were recorded. We discuss the problems of NIPT on the basis of published reports and meta-analyses. RESULTS: From April 2013 to March 2016, 30 613 tests were conducted at 55 medical sites participating in a multicenter clinical study. Among the 30 613 women tested, 554 were positive (1.81%) and 30 021 were negative (98.1%) for aneuploidy. Of the 289, 128, and 44 women who tested positive for trisomies 21, 18, and 13, respectively, and underwent definitive testing, 279 (96.5%), 106 (82.8%), and 28 (63.6%) were determined to have a true-positive result. For the 13 481 women with negative result and whose progress could be traced, two had a false-negative result (0.02%). The tests were performed on the condition that a standard level of genetic counseling be provided at hospitals. CONCLUSION: Here, we report on the 3-year nationwide experience with NIPT in Japan. It is important to establish a genetic counseling system to enable women to make informed decisions regarding prenatal testing. Moreover, a welfare system is warranted to support women who decide to give birth to and raise children with chromosomal diseases.

Fetal cell-free DNA fraction in maternal plasma is affected by fetal trisomy.

The purpose of this noninvasive prenatal testing (NIPT) study was to compare the fetal fraction of singleton gestations by gestational age, maternal characteristics and chromosome-specific aneuploidies as indicated by z-scores. This study was a multicenter prospective cohort study. Test data were collected from women who underwent NIPT by the massively parallel sequencing method. We used sequencing-based fetal fraction calculations in which we estimated fetal DNA fraction by simply counting the number of reads aligned within specific autosomal regions and applying a weighting scheme derived from a multivariate model. Relationships between fetal fractions and gestational age, maternal weight and height, and z-scores for chromosomes 21, 18 and 13 were assessed. A total of 7740 pregnant women enrolled in the study, of which 6993 met the study criteria. As expected, fetal fraction was inversely correlated with maternal weight (P<0.001). The median fetal fraction of samples with euploid result (n=6850) and trisomy 21 (n=70) were 13.7% and 13.6%, respectively. In contrast, the median fetal fraction values for samples with trisomies 18 (n=35) and 13 (n=9) were 11.0% and 8.0%, respectively. The fetal fraction of samples with trisomy 21 NIPT result is comparable to that of samples with euploid result. However, the fetal fractions of samples with trisomies 13 and 18 are significantly lower compared with that of euploid result. We conclude that it may make detecting these two trisomies more challenging.

A survey on awareness of genetic counseling for non-invasive prenatal testing: the first year experience in Japan.

The purpose of this study is to summarize the results from a survey on awareness of genetic counseling for pregnant women who wish to receive non-invasive prenatal testing (NIPT) in Japan. As a component of a clinical study by the Japan NIPT Consortium, genetic counseling was conducted for women who wished to receive NIPT, and a questionnaire concerning both NIPT and genetic counseling was given twice: once after pre-test counseling and again when test results were reported. The responses of 7292 women were analyzed. They expressed high satisfaction with the genetic counseling system of the NIPT Consortium (94%). The number of respondents who indicated that genetic counseling is necessary for NIPT increased over time. Furthermore, they highly valued genetic counseling provided by skilled clinicians, such as clinical geneticists or genetic counselors. The vast majority (90%) responded that there was sufficient opportunity to consider the test ahead of time. Meanwhile, women who received positive test results had a poor opinion and expressed a low-degree satisfaction. We confirmed that the pre-test genetic counseling that we conducted creates an opportunity for pregnant women to sufficiently consider prenatal testing, promotes its understanding and has possibilities to effectively facilitate informed decision making after adequate consideration. A more careful and thorough approach is considered to be necessary for women who received positive test results.

Factors affecting parental decisions to terminate pregnancy in the presence of chromosome abnormalities: a Japanese multicenter study.

OBJECTIVE: To investigate the rates of termination of pregnancy (TOP) for fetal chromosomal abnormalities and factors related to such parental decision in Japan. METHODS: A multicenter retrospective cohort study of chromosomal abnormalities diagnosed before 22 weeks of gestation between April 2008 and March 2015. The pregnancy outcomes and parental decisions were investigated. RESULTS: Among 931 fetuses with chromosome abnormalities, the total TOP rate was 75.1% (699/931). TOP rates were 89.3% (585/655) in autosomal aneuploidies and 40.8% (51/125) in sex chromosome aneuploidies. Trisomy 21 showed the highest TOP rate (93.8% [390/416]) followed by trisomy 18 (84.5% [163/193]) and trisomy 13 (71.9% [23/32]). Indications for karyotyping were related to a parental decision for TOP (p < 0.01): in cases of autosomal aneuploidy, with fetal abnormal ultrasound findings as the reference value, diagnoses made following positive results at non-invasive prenatal testing (adjusted odds ratio [OR]: 13.7, 95% confidence interval [CI] 4.07-45.9) and those because of advanced maternal age (adj. OR 2.91, 95% CI 1.15-7.35) were significantly more frequent. CONCLUSIONS: In Japan, pregnancies with fetal trisomy 21 are more likely to result in TOP when diagnosed in utero than any other chromosome anomaly. The indications for prenatal karyotyping strongly affect the decision to TOP. © 2016 John Wiley & Sons, Ltd.

Background of couples undergoing non-invasive prenatal testing in Japan.

AIM: Our purpose was to assess the background of couples who were undergoing non-invasive prenatal testing (NIPT) in Japan. METHODS: The characteristics of 2486 women who had visited Nagoya City University Hospital for NIPT were compared with Japanese Demographic Trends as controls. The questionnaire included items regarding the maternal and paternal age, maternal age at marriage, age at first live birth, and conception mode. RESULTS: Compared with the controls, the percentage of women who were 4 or more years older than their partners was larger in the NIPT group (11.8% vs 6.5%). The maternal age at marriage, age at first live birth, and the duration between marriage and first birth tended to be greater in the NIPT group (32.6 years vs 29.3 years, 36.9 years vs 30.4 years, and 3.6 years vs 2.4 years, respectively), and the percentage of women who underwent assisted reproductive technology tended to be higher in the NIPT group (35-39 years: 21.2% vs 7.5%, 40-45 years: 36.2% vs 12.6%), compared with the controls. CONCLUSION: Knowing the specific backgrounds of couples who have undergone NIPT may be important for improving the quality of genetic counseling for NIPT.

Parental decisions following prenatal diagnosis of chromosomal abnormalities: implications for genetic counseling practice in Japan.

Parental decision-making to terminate or continue a pregnancy was studied after prenatal diagnosis of a chromosome aneuploidy among a sample of patients around the city of Nagoya, Japan. A total of 1,051 amniocentesis cases at 15-18 weeks of gestation were analyzed. Of these, 60 cases of chromosomal anomalies with aneuploidies were diagnosed by conventional cytogenetic analysis. Of the 45 diagnoses of autosomal chromosome aneuploidies, pregnancy was terminated in 93.3 % of the cases. Of the 15 cases diagnosed with sex chromosome aneuploidy, pregnancy was terminated in 46.7 %. Differences in parental decisions with respect to maternal age, gestational week at diagnosis, number of pregnancies per individual and existing number of children were not significant in patients diagnosed either with autosomal or sex chromosome aneuploidy. The findings indicate that when diagnosed with a chromosome aneuploidy in which a severe prognosis was expected, most couples decided to terminate the pregnancy in Japan. Implications of these findings for expanding the profession of genetic counseling are discussed and research recommendations are provided.