The Pre-Pregnancy Risk Factors of Stillbirth in Pregnant Iranian Women: A Population-Based Case-Control Study

Abstract

Background: Stillbirth is an important economic, cultural, and health index that has a higher prevalence in developing countries. Objectives: The present research was conducted to determine the pre-pregnancy risk factors of stillbirth in Iran. Methods: This research is a national population-based case-control study on the risk factors of stillbirth in Iran. A total of 3,085 women presenting to public healthcare centers of ten provinces/cities of Iran entered the study, including 1,459 women who their last pregnancy ended in a stillbirth as the case group and 1,626 women who their last pregnancy ended in a live birth as the control group. Data were collected with a researcher-made questionnaire and were then analyzed by SPSS-19 using the chi-square and the logistic regression tests. P values less than 0.05 were considered statistically significant. Results: The results revealed a relationship between the last pregnancy ending in a stillbirth and a previous history of stillbirth (OR = 2.64, CI: 1.81 - 3.85, P = 0.001), miscarriage (OR = 1.57, CI: 1.21 - 2.03, P = 0.001) irregular menstruation (OR = 1.29, CI: 1.02 - 1.64, P = 0.029), age over 35 (OR = 1.58, CI: 1.17 - 2.14, P = 0.001), low level of education (OR = 3.50, CI: 2.30 - 5.33, P = 0.001), and the use of oral contraceptives. Conclusions: There are several risk factors for stillbirth, including a previous history of stillbirth, miscarriage or irregular menstrual cycle, most of which can be controlled through pre-pregnancy training. Educational interventions are, therefore, required to improve the knowledge of women at childbearing age and preventive measures should be taken to reduce the number of stillbirths in pregnant women.