Trends in chromosomal anomalies for live births and prenatal diagnoses in Latvia

Screening for fetal chromosomal abnormalities is an essential part of antenatal care. It includes non-invasive approaches as well as invasive procedures for the definitive prenatal diagnosis of disorders. During the last decades, an increasing number of congenital anomalies have been diagnosed before birth by prenatal screening. Down syndrome (DS) is the most common chromosomal aberration detected in prenatal testing. The aim: To describe trends of DS and other chromosomal anomalies (ChA) for live births and antenatal diagnoses in Latvia over the last 10 years. Data source was Register of Patients with Particular Diseases, Patients with Congenital anomalies. All live newborns, which were born (2010–2019) and were diagnosed chromosomal anomalies [ICD‐10: Q90-Q99] (n = 373) and termination of pregnancy for anomalies following prenatal diagnosis (TOPFA) (n = 461) data were included. Live birth (LB) and TOPFA period prevalence of DS and ChA was calculated. The most common chromosomal anomaly is Down syndrom (DS). A total of 177 cases for LB with DS and 281 for TOPFA were included in data analysis. Ten year LB period prevalence with DS was 8.8/10000 (95%CI 7.6-10.2) and TOPHA 13.9/10000 (95%CI 12.4-15.6) (per live and stillbirths). ChA period prevalence for LB was 9.8/10000 (95%CI 8.4-11.2) and 8.9/10000 (95%CI 7.7-10.3) for TOPHA. There are statistically significant DS prevalence trends observed over the study period. LB prevalence with DS has shown slight reduction (p<0.05), an average 0.8/10000 contrary to TOPFA – increase an average 2.2/10000 per year (p<0.001). The same situation was with ChA TOPHA increase by 2.0/10000 per year (p<0.001) but not significant trends for LB with ChA. Prevalence decrease of LB with DS is the result of improvements in antenatal care and prenatal screening thereby an increasing number of pregnancies are terminated. Pregnant women are given a choice between termination or continuation of pregnancy.