Risk Factors of Stillbirths: A Case Control Study in North India

Abstract

Abstract Introduction: Stillbirth is not appreciated as a public health problem and given a high priority by the policy makers despite 2.6 million fetal deaths annually worldwide. About 98% stillbirths occur in Low and Middle Income Countries (LMIC). India is the largest contributor of all global stillbirths. The study aims to evaluate risk factors of stillbirths. Materials and Methods: A hospital-based case-control study was conducted in medical college women’s hospital in north India. The cases were mothers of stillborn babies. There were 38 stillbirths during the study period. Mother of liveborn babies were taken as controls. For each case, two controls were selected (76) from the same hospital during the corresponding time. The power of the sample was 80 percent at 95 percent confidence limit. The cases and controls were comparable, the respective mean age of mothers being 25.3 (+SD 3.7) and 23.9 (+SD 4.6) years (p >0.05). Bivariate analysis was carried out with stillbirth as outcome variable and age, sex of the baby, residence, maternal complications and fetal characteristics as independent variables. Rural residence, sex of the baby, pregnancy induced hypertension/eclampsia and preterm deliveries were statistically significantly associated with occurrence of stillbirth. Multivariate logistic regression was performed, and risk was estimated by measuring Odds Ratio (OR). The model included variables which were statistically significant on bivariate analysis. Results: The risk of stillbirth was 10 times or more with pregnancy induced hypertension and preterm delivery, the adjusted OR being 12.75 (95% CI 2.95-55.00; p <0.001) and 12.54 (95% CI 3.95-39.00; p <0.001). Higher maternal age was also associated with significantly higher and independent risk of stillbirth (OR 1.90, 95% CI 1.10-3.27; p <0.02). Male fetus was more likely to be stillborn (OR 4.02, 95% CI 1.38-11.69). There effect was independent of all other risk factors in the model. The effect of rural residence was not significant in multivariate model. Conclusion: The study showed a strong evidence of association pregnancy induced hypertension and preterm birth as risk factors for stillbirth. Maternal age and sex of the child also showed statistically significant risk of stillbirth. Rural residence which showed significant association in bivariate analysis, but it was removed in the model when adjusted for other risk factors. Keywords Case control; Multivariate regression model; Odds ratio; Risk factors; Stillbirth