This study was undertaken to determi ne uterine and fetal heart rate(FHR)tracing patterns associated with clinically apparent uterine leiomyomas.Uterine and FHR patterns of44women with diagnosed uterine leio myomas were com-pared with 601tracings of controls.Tracings were inter-preted during the first stage of labor,using the National Institute of Child Health and Human Development Research Planning Workshop guidelines.Stra tified analysis that used the Mantel -Haenszel technique was p erformed to control for confounders.Patients with leio myomas had higher rates of uterine tachysystole as compared with those without leiomyomas(22.7%vs 1.3%;odds ratioOR=21.8,95%CI 7.4-65.6;P <.001).No significant differ-ences were noted between the groups r egarding FHR pat-terns.Higher rates’of prostaglandin induction and oxytocin augmentation were noted in the uterine leiomyomas group(6.8%vs 0.8%;P =.005and 52.3%vs 10.5%;P<.001,respectively).However,controlling for prostag-landin induction and oxytocin augme ntation,with the use of the Mantel -Haenszel procedure,did not change the sig-nificant association between uterine leiomyomas and tachysystole(weighted OR 12.5,95%CI 6.2-75.1,an d weighted OR 8.7,95%CI 3.6-43.1,respectively).Clinically apparent uterine leiomy omas,although not cou-pled with abnormal FHR patterns,are associated with higher rates of tachysystole. This study was undertaken to determine neurectomy and fetal heart rate (FHR) tracing patterns associated with clinically apparent uterine leiomyomas. Uterine and FHR patterns of 44 women with diagnosed uterine leio myomas were com-pared with 601 transcings of controls. Articles were inter-preted during the first stage of labor, using the National Institute of Child Health and Human Development Research Planning Workshop guidelines. Stratified analysis that used the Mantel -Haenszel technique was p erformed to control for confounders. Patients with leio myomas had higher rates of uterine tachysystole as compared with those without leiomyomas (22.7% vs 1.3%; odds ratioOR = 21.8, 95% CI 7.4-65.6; P <.001) .No significant differ- ences were noted between the groups r egarding FHR pat- terns. prostaglandin induction and oxytocin augmentation were noted in the uterine leiomyomas group (6.8% vs 0.8%; P = .005 and 52.3% vs 10.5%; P <.001, respectively) .owever, controlling for prostaglandin induction and oxytoc in augment ntation, with the use of the Mantel -Haenszel procedure, did not change the sig-nificant association between uterine leiomyomas and tachysystole (weighted OR 12.5, 95% CI 6.2-75.1, an d weighted OR 8.7, 95% CI 3.6- 43.1, respectively) .Clinically apparent uterine leiomy omas, although not cou-pled with abnormal FHR patterns, are associated with higher rates of tachysystole.