Perinatal mortality in relation to birthweight and gestational age: a registry‐based comparison of Northern Norway and Murmansk County, Russia

Abstract

The objective was to explore how perinatal mortality relates to birthweight, gestational age and optimal perinatal survival weight for two Arctic populations employing an existing and a newly established birth registry. A medical birth registry for all births in Murmansk County of North-West Russia became operational on 1st January 2006. Its primary function is to provide useful information for health care officials pertinent to improving perinatal care. The cohort studied consisted of 17,302 births in 2006-07 (Murmansk County) and 16,006 in 2004-06 (Northern Norway). Birthweight probability density functions were analysed, and logistic regression models were employed to calculate gestational-age-specific mortality ratios. The perinatal mortality rate was 10.7/1000 in Murmansk County and 5.7/1000 in Northern Norway. Murmansk County had a higher proportion of preterm deliveries (8.7%) compared to Northern Norway (6.6%). The odds ratio (OR) of risk of mortality (Northern Norway as the reference group) was higher for all gestational ages in Murmansk County, but the largest risk difference occurred among term deliveries (OR 2.45, 95% confidence interval 1.45, 4.14) which hardly changed on adjustment for maternal age, parity and gestation. Proportionately, more babies were born near (± 500 g) the optimal perinatal survival weight in Murmansk County (67.2%) than in Northern Norway (47.6%). The observed perinatal mortality was higher in Murmansk County at all birthweight strata and at gestational ages between weeks 25 and 42, but the adjusted risk difference was most significant for term deliveries.

Congenital anomalies of the kidney and the urinary tract: A murmansk county birth registry study

“…These recorded sources have previously been described in detail (Anda et al, 2008;Anda et al, 2011), and their quality was determined to be satisfactory for epidemiological research. dos Santos Junior et al, 2014).…”

Maternal Risk Factors for Preterm Birth in Murmansk County, Russia: A Registry‐Based Study

“…We treated sociodemographic and life style maternal characteristics as categorical variables, which included: maternal age (<18, 18-34, ≥35 years); education (none or primary [class [1][2][3][4][5][6][7][8][9], secondary [class [10][11], vocational school, higher); cigarette smoking, and alcohol abuse during pregnancy (yes/no). We categorised civil status as single, married, and cohabiting; the first category included divorced and separated women.…”

“…In the city of Severodvinsk (Arkhangelsk County), 5.6% of spontaneous live singleton births were preterm, 5 while in Murmansk County the prevalence of PTB was higher (8.7%) but included stillbirths. 6 In Syktyvkar (the capital of Komi Republic, located next to Arkhangelsk County), the PTB prevalence (from 28 weeks of gestation on) comprised 4.9 and 5.8% in 1980-84 and 1995-99, respectively. 7 Preterm birth is a major contributor to under fiveyear mortality and morbidity, especially those births that take place before 34 weeks of gestation.…”

Early pregnancy body mass index and spontaneous preterm birth in Northwest Russia: a registry-based study

“…The prevalence of PTB is 11-12.9% worldwide [4, 5] and 6.2% in Europe [5] while Russian studies have reported a prevalence of 5.2- 8.7% [6–8]. PTB is one of the main contributors to neonatal mortality, neonatal morbidity and childhood morbidity and is associated with considerable burden for health care system [9].…”