- The objective was to determine if uterine leiomyoma increases the risk of cesarean section (CS) among women who conceived following fertility treatment. The study population consisted of all women who conceived after fertility treatment with singleton gestation and who delivered between the years 1988 and 1999 in the Soroka University Medical Center. A comparison was performed between patients with and without uterine leiomyomas. The Mantel-Haenszel procedure was used to obtain the weighted odds ratio (OR) for CS, while controlling for confounding variables. During the study period 1,995 women conceived following fertility treatment. Of these, 63 patients had uterine leiomyomas (3.2%). Women treated for fertility with uterine leiomyomas had statistically significant higher rates of CS than those without uterine leiomyomas (61.9% vs. 28.1%, OR=4.2, 95% CI 2.4-7.2; P<0.001). Stratified analysis (the Mantel-Haenszel technique) was used to control for possible confounders, such as gestational diabetes, hypertensive disorders, maternal age, failure of labor to progress, placental abruption, malpresentation, hydramnios, oligohydramnios, and a previous CS. None of those variables changed the significant association or explained the higher incidence of CS in the uterine leiomyoma group. Uterine leiomyoma is an independent risk factor for CS among women who conceived following fertility treatment.