Junko Yotsumoto

Attitudes toward non‐invasive prenatal diagnosis among pregnant women and health professionals in Japan

This study aims to assess the attitudes toward non‐invasive prenatal diagnosis (NIPD) and NIPD problems in clinical practice in Japan.

Placental expression of microRNA-17 and -19b is down-regulated in early pregnancy loss.

OBJECTIVE First, to determine if microRNA-17 and -19b are expressed in villous samples at early stages of pregnancy. Second, to determine whether placental expressions of these microRNAs along with their main targets (PTEN, CREB-1, TGFβ-1 and TGFβ-RII) are altered in early pregnancy loss. STUDY DESIGN Expression levels of microRNAs and mRNA targets in villous samples from early pregnancy loss (n=11) and matched normal cases (n=20) by gestational age were determined by RT-PCR. RESULTS Both microRNA-17 and -19b were expressed in all cases of normal pregnancy. They were significantly down-regulated (relative ratios: 0.35 and 0.34 respectively) in early pregnancy loss. Their main target, PTEN mRNA, was significantly up-regulated in early pregnancy loss (relative ratio: 2.6, 95%CI: 0.2-29.8). TGF-β1, CREB-1 and TGFβ-RII were not significantly different between the two groups. CONCLUSION microRNA-17 and -19b are expressed in early stages of pregnancy. They are down-regulated in villous samples from early pregnancy loss. We suggest that these main members of the microRNA-17-92 cluster might be involved in placental invasion and its dysregulation might also be related to other conditions characterized by defective placentation.

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.

Physiological changes in the pattern of placental gene expression early in the first trimester.

Objective: To assess the physiological changes in the placental expression pattern of a panel of genes related to angiogenesis and oxidative stress during the early part of the first trimester of pregnancy. Methods and Results: The expression of a selected panel of genes was quantified by reverse transcriptase–polymerase chain reaction in samples of villous trophoblasts obtained from women between 6 and 11 weeks of gestation undergoing elective artificial abortion. We found that the levels of messenger RNA (mRNA) expression of placental growth factor (PlGF), heme oxygenase 1(HO-1), and superoxide dismutase (SOD) increased significantly with gestational age (r = .37, P = .001; r = .24, P =.04; and r = .52, P < .001, respectively). Conversely, the mRNA expression level of fms-like tyrosine kinase 1 (FLT-1) decreased significantly (r = −.30, P = .009). Conclusion: During the early part of the first trimester of pregnancy, the placental gene expression levels of PlGF, HO-1, and SOD increase with gestational age, whereas the expression of FLT-1 decreases. The alteration in this pattern of gene expression in early pregnancy may therefore play an important role in placenta-related disorders such as preeclampsia.

Maternal smoking and placental expression of a panel of genes related to angiogenesis and oxidative stress in early pregnancy.

Objective: Maternal cigarette smoking is paradoxically associated with a decreased risk of developing preeclampsia. Since preeclampsia is thought to be associated with altered mechanisms of angiogenesis and oxidative stress, we aim to investigate the influence of maternal smoking on the early placental expression of a panel of genes related to angiogenesis and oxidative stress. Material and Methods: We collected villous tissue samples at 6-7 and 10-11 weeks of gestation from 31 women requesting surgical termination. Placental expression of the following genes were quantified by real-time PCR: vascular endothelial growth factor A (VEGFA), fms-like tyrosine kinase (Flt-1), soluble endoglin (sEng), placental growth factor (PlGF), heme oxygenase-1 (HMOX-1) and superoxide dismutase (SOD). Maternal smoking status was assessed by levels of serum cotinine. Results: Placental expression of VEGFA was significantly higher in smoking women at 10-11 weeks of gestation compared with nonsmoking women at the same gestational age. There was no significant difference at 6-7 weeks of gestation. There was no variation in the expression of the other genes explored related to smoking status. Conclusions: Here we report that VEGFA placental expression was higher in smoking women at 10-11 weeks of gestation. Increased VEGFA expression in the early stages of pregnancy in smoking women might contribute to the decreased risk of developing preeclampsia.

Chromosome abnormalities diagnosed in utero : a Japanese study of 28 983 amniotic fluid specimens collected before 22 weeks gestations

To investigate the frequency and type of abnormal karyotype in Japan by amniocentesis before 22 weeks of gestation. We performed a retrospective analysis of 28 983 amniotic fluid specimens in a local population collected before 22 weeks gestations for fetal karyotyping. The incidence of abnormal karyotype was 6.0%. The main indication was advanced maternal age (AMA) of 35 years and older, which represented over half of the clinical indications. Abnormal karyotype was most frequently reported among the referrals for abnormal ultrasound findings (21.8%), followed by positive maternal serum screen results (5.3%). Three-fourths of abnormal karyotype was either autosomal aneuploidy (64.0%) or sex chromosome aneuploidy (11.6%). Abnormal karyotype was detected in 2.8% of pregnant women referred for AMA. Clinically significant abnormal karyotype increased with advancing maternal age. The frequency and type of abnormal karyotype detected by amniocentesis for various indications were determined. Amniocentesis was mainly performed among the referrals for AMA, which is a characteristic distribution of indications of Japan.

Current status of non‐invasive prenatal testing in Japan

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.

Background of couples undergoing non‐invasive prenatal testing in Japan

Our purpose was to assess the background of couples who were undergoing non‐invasive prenatal testing (NIPT) in Japan.

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.

Survey of second‐trimester maternal serum screening in Japan

Second‐trimester maternal serum screening (MSS) is the predominant form of prenatal screening in Japan. We hypothesize that patient education and physician knowledge of Down syndrome (DS) screening are insufficient to provide adequate information regarding prenatal screening in Japan.