Estonian medical birth registry 1992-1994: association of risk factors with perinatal mortality

Abstract

Objective: To investigate the association of different maternal sociodemographic characteristics and infant sex with perinatal mortality among primiparas and multiparas.

Study design: Analysis of routine data from the Estonian Medical Birth Registry covering the whole of Estonia. A total of 47 358 infants (including stillborns) with a birth weight 1000 g or more from 1992 through 1994 were studied. Perinatal mortality rate, crude odds ratio (OR) and adjusted OR (calculated by a logistic regression model) were used to evaluate the association. OR values were adjusted for maternal age at delivery, maternal ethnicity, educational level, residence, marital status, smoking status, history of previous abortion and infant sex.

Results: The perinatal mortality rate was 12.2 per 1000 total births among primiparous and 14.3 among multiparous women. The highest adjusted ORs of perinatal deaths were found in older (35 years and over) primiparas (1.78; 95% confidence interval (CI 0.88-3.57)) and multiparas (1.81; 95% CI 1.29-2.55), in unmarried (single) primiparas (1.59; 95% CI 1.14-2.20) and multiparas (1.98; 95% CI 1.29-3.05), in smoking primiparas (1.69; 95% CI 1.09-2.63) and multiparas (1.51; 95% CI 1.02-2.25), and in multiparas with unknown smoking status (1.98; 95% CI 1.18-3.33).

Conclusion: The study provides further evidence that perinatal mortality is positively associated with increased maternal age, unmarried (single) status and smoking.

PIP: This study was conducted to investigate the association of different maternal sociodemographic characteristics and infant sex with perinatal mortality among primiparas and multiparas. The data were based on the Estonian Medical Birth Registry (EMBR) which maintains a database of all infants born in hospitals and of the few home deliveries. From 1992 to 1994, 47,022 live births and 336 stillbirths were recorded in the EMBR. Of mothers younger than 20 years old, 26.5% were primiparous and 2.8% were multiparous; among mothers aged 35 years and older, 1.8% were primiparous and 12.0% were multiparous. Results showed that the perinatal mortality rate was 12.2%/1000 total births among primiparous and 14.3% among multiparous women. The highest adjusted odds ratios of perinatal deaths were found in older (35 years and up) primiparas (79%) and multiparas (1.8%); in unmarried primiparas (1.5%) and multiparas (2.0%); in smoking primiparas (1.7%) and multiparas (1.5%); and in multiparas with unknown smoking status (2.0)%. Therefore, perinatal mortality in Estonia was positively associated with increased maternal age, unmarried (single) status, and smoking.