Equipoise of recent estimated Down syndrome live births in Japan

Abstract

To support people with Down syndrome (DS), it is essential to know and predict the number of live births of children with this condition. In this study, we estimated DS live birth rates on the basis of maternal age distribution and numbers of births in the general population, the maternal-age specific chance for a live birth of a child with DS, and the prenatal diagnosis/termination rate. The total number of live births in Japan decreased to less than 1 million in 2016 and the percentage of women aged 35 years old or over giving birth has increased by sixfold. Prenatal genetic testing in Japan has gradually become more widespread, and 20% of all cases of DS were diagnosed prenatally in 2016. Meanwhile, the annual projected number of DS live births has remained steady at around 2,200 (22 per 10,000 births). In 2016, it was estimated that 70% of all DS babies were born to women of advanced maternal age (AMA). Given that Japan is facing a decreasing birth rate and an aging population, adoption of the practice of prenatal genetic testing for AMA has balanced the number of DS births over the last 7 years from 2010. K E Y W O R D Sadvanced maternal age, Down syndrome, live birth, prenatal genetic testing, trisomy 21

Changes in awareness and knowledge concerning mother-to-child infections among Japanese pregnant women between 2012 and 2018

“…Congenital infection is a common cause of neonatal morbidity and mortality. For example, the estimated incidence of the congenital cytomegalovirus (CMV) infection in Japan was reported to be 30 per 10,000 births between 2008 and 2010 [1], which is more frequent in comparison to trisomy 21 during the same period (i.e., 22 per 10,000 births) [2]. Meanwhile, in a nationwide survey investigating the incidence of congenital infections, Yamada et al clarified the reported incidence of congenital infections among 34 cases with CMV and 1 with Toxoplasma gondii (T. gondii) from 2714 obstetric facilities in Japan.…”

Secular trends in longevity among people with Down syndrome in Japan, 1995–2016

“…Down syndrome is the most common chromosomal abnormality in Japan 1 and occurs in 28.3/10 000 of all pregnancies. 2 It is associated with a variety of congenital malformations including heart defects (observed in 40-60% of the population), [3][4][5] duodenal atresia, anorectal malformations, hypospadias, and cataracts. 6 Down syndrome is also known to increase the risks of developing many diseases later in life, such as respiratory infections, obstructive sleep apnea, dementia, and leukemia.…”

Hospitalisations due to respiratory syncytial virus infection in children with Down syndrome before and after palivizumab recommendation in Japan

“…The projected number of live births with Down syndrome remained around 2200 per year between 2010 and 2016 in Japan 1 ; therefore, about 30% of them could be analysed in this study. Half of the children with Down syndrome were known to have CHD with or without abnormal haemodynamics, 8 and similarly 59.5% had it in this study.…”

“…Down syndrome is the most common chromosomal abnormality among live‐born infants and has an estimated annual prevalence of 22 per 10,000 births in Japan 1 . The prevalence of Down syndrome live births in Japan shows a slight increase which is higher than other countries 1 . Children with Down syndrome have anatomical and physiological abnormalities which contribute to an increased susceptibility to respiratory infections.…”