Determinants of placenta previa: a case-control study

Abstract

Background: The risk factors of placenta previa differ around the world. This study evaluated risk factors of pregnancies complicated with placenta previa during a 5-year period in a referral center in Hamadan, Iran. Methods: This case control study was conducted in Hamadan city (Hamadan Province of Iran) from April 2013 to March 2017. The cases were women whose deliveries were complicated by placenta previa and the controls were those who delivered without placenta previa. We recruited 130 cases and 130 controls. Multivariate unconditional logistic regression analysis was conducted, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Results: The OR of placenta previa was 4.08 (95% CI= 1.44, 11.58) by maternal age, 4.08 (95% CI =1.44, 11.58) by preterm labor, and 6.64 (95% CI =1.09, 40.45) by prior operations of the uterine cavity, compared to normal deliveries and after adjusting for other variables. Multiparity, prior spontaneous abortions, and prior cesarean sections were not statistically significant risk factors for placenta previa, when adjusted for other variables.  Conclusion: Our study suggests that high maternal age and prior operations of the uterine cavity are risk factors for placenta previa.