Changes in detection of birth defects and perinatal mortality after introduction of prenatal ultrasound screening in the Kola Peninsula (North-West Russia): combination of two birth registries

BACKGROUND Prenatal diagnostics ultrasound was established in Russia in 2000 as a routine method of screening for birth defects. The aims of the current study were twofold: to assess changes in birth defects prevalence at birth and perinatal mortality after ultrasound screening was implemented and to estimate prenatal detection rates for congenital malformations in the city of Monchegorsk (Murmansk County, North-West Russia). METHODS The Murmansk County Birth Registry and the Kola Birth Registry were the primary sources of information, and include 30 448 pregnancy outcomes in Monchegorsk for the period 1973-2011. Data from these registries were supplemented with information derived from hospital records about pregnancy terminations for 2000-2007. RESULTS The total number of newborns with any kind of birth defects in Monchegorsk during 1973-2011 was 1099, of whom 816 were born in the 1973-2000 period. The prevalence of defects at birth increased from 34.2/1000 (95% CI = 31.9-36.5) to 42.8/1000 newborns (95% CI = 38.0-47.7) after prenatal ultrasound screening was formally implemented. We observed significant decreases (p < 0.05) in the birth prevalence of congenital malformations of the circulatory system, the musculoskeletal system (including deformations), and other (excluding multiple); those of the urinary system increased from 0.9/1000 to 17.1/1000 (p < 0.0001). The perinatal mortality among newborns with any kind of malformation decreased from 106.6 per 1000 newborns with birth defects (95% CI = 84.3-129.1) to 21.2 (95 % CI = 4.3-38.1). Mothers who had undergone at least one ultrasound examination during pregnancy (n = 9883) had a decreased risk of having a newborn die during the perinatal period [adjusted OR = 0.49 (95% CI = 0.27-0.89)]. The overall prenatal detection rate was 34.9% with the highest for malformations of the nervous system. CONCLUSION Improved detection of severe malformations with subsequent pregnancy termination was likely the main contributor to the observed decrease in perinatal mortality in Murmansk County, Russia.