Investigation of Risk Factors for Preeclampsia Development Among Reproductive Age Women Living in Yerevan, Armenia: A Case-Control Study

Abstract

Introduction: Preeclampsia is a hypertensive disorder of pregnancy of unknown etiology. Worldwide, each year, more than four million women develop preeclampsia and in developing countries, where prenatal care is not adequate, preeclampsia/eclampsia accounts for 40% to 80% of maternal deaths, accounting for about 50,000 deaths yearly. Objective: To measure the association of parity and interbirth interval (IBI) with preeclampsia status and their interactions with other covariates among reproductive age (18-45) women living in Yerevan. Methods: The study utilized a case-control study design. Cases (n=89) were reproductive age women living in Yerevan that were diagnosed with preeclampsia in the Institute of Obstetrics (Perinatology), Gynecology and Reproductive Health and the Erebuni Medical Center from 01.01.2008 to 01.04.09. Controls (n=279) were reproductive age women living in Yerevan that gave birth in the same maternity homes with no diagnosis of preeclampsia during pregnancy within the same time period. The study conducted telephone based interviews with both cases and controls through structured questionnaire developed by the research team. Data analysis was performed using STATA software. Results: The odds of preeclampsia was lower among multiparous women compared to primiparous women (OR=0.27; 95% CI: 0.14, 0.51; p=0.000) after adjusting for age, Body Mass Index (BMI), number of people living in the household and number of employed family members. After adjusting for age, BMI, renal disease the odds of preeclampsia was higher among women with long IBI compared to women with short IBI (OR=2.90; 95% CI: 1.07, 7.86; p=0.036). The interaction term between IBI and the history of previous preeclampsia was 0.11 (95% CI: 0.01, 1.01; p=0.051). Conclusions: The results showed that parity and IBI were statistically significantly associated with preeclampsia status after controlling for confounders. This study confirmed that the risk of preeclampsia falls sharply after the first birth but it also showed that the risk increased over time and that long IBI was associated with higher risk of preeclampsia development. However, for women without history of previous preeclampsia the risk of preeclampsia increased in subsequent pregnancy with increasing time between births whereas for women with history of previous preeclampsia the risk tended to decrease with increasing interval between births.