Combined first-trimester screening in northern Finland: experiences of the first ten years

Down Syndrome in Brazil: Occurrence and Associated Factors

Background: Down syndrome is the most frequent genetic cause of intellectual disability, with an estimated birth prevalence of 14 per 10,000 live births. In Brazil, statistical data on the occurrence of babies born with Down syndrome remain unclear. We aimed to estimate the occurrence of Down syndrome between 2012 and 2018, and to observe its association with maternal, gestational, paternal characteristics, and newborn vitality. Methods: A retrospective study was carried out using secondary data included in the Certificate of Live Birth in a state located in the southeastern region of Brazil. Data analysis was performed in the software Stata 14.1. Pearson’s chi-square test for bivariate analysis, and logistic regression for multivariate analysis were performed, with a 95% confidence interval (CI) and a significance of 5%. Results: We observed that 157 cases of Down syndrome were reported among 386,571 live births, representing an incidence of 4 in 10,000 live births. Down syndrome was associated with maternal age ≥ 35 years, paternal age ≥ 30 years, the performance of six or more prenatal consultations, prematurity, and low birth weight (p < 0.05). Conclusions: Women aged 35 and over were more likely to have children born with Down syndrome. In addition, there is an association of Down syndrome with premature birth, low birth weight, and the number of prenatal consultations (≥6).

Impact of prenatal screening on the prevalence of Down syndrome in Slovenia

OBJECTIVES

To evaluate the impact of prenatal screening and genetic testing for trisomy 21 (T21) on the prevalence of T21 in Slovenia.

DESIGN AND SETTING

Data about all prenatally and postnatally confirmed cases of T21 in Slovenia between 1981 and 2012 were collected retrospectively from all genetic laboratories in Slovenia. The expected number of babies with T21 according to maternal age was calculated.

MAIN OUTCOME MEASURES

The primary outcomes measures were number of fetuses and newborn infants with T21 diagnosed prenatally and postnatally and the impact of advances in screening and genetic diagnostics on the prevalence of newborns with T21 in Slovenia.

RESULTS

Despite a significantly increased mean maternal age from 25.4 years in year 1981 to 30.3 years in year 2012 the prevalence of newborn infants with T21 was 0.51 per 1000 births compared to 0.55 per 1000 births, respectively. The prevalence of prenatally diagnosed cases increased from 0.03 per 1000 births to 2.06 per 1000. The detection rate of T21 in year 2012 was 78,9%. The total number of prenatal invasive procedures (chorionic villous sampling and amniocenteses) carried out during that period was rising until 2002, since when it is stable at around 7%.

CONCLUSION

The advancement and implementation of screening tests and prenatal diagnostic procedures in Slovenia caused an important improvement in the efficiency of the prenatal detection of T21.