The irritable uterus: a risk factor for preterm birth?

Abstract

Our aim was to determine the incidence and preterm delivery rate along with the indication for delivery in patients with uterine irritability. In this retrospective, descriptive study, 17,186 patients with well-defined high-risk factors were compared with 2637 women with uterine irritability. The incidence of preterm labor in patients with uterine irritability was 18.7%, significantly less than in those with other high-risk factors (odds ratio 0.35, 0.31 < odds ratio < 0.38). However, women with uterine irritability who experience preterm labor, compared with other high-risk factors, are much more likely to deliver before 34 weeks' gestation (odds ratio 2.50, 2.07 < odds ratio < 3.03) and more than twice as likely to deliver as a result of advanced preterm labor or membrane rupture (odds ratio 2.20, 1.75 < odds ratio < 2.78). The incidence of preterm labor in women with uterine irritability is not as frequent as in patients with other high-risk factors. However, preterm labor does occur in patients with uterine irritability at a rate higher than that in the general obstetric population (18.7% vs 11.0%). Because it appears that women with uterine irritability have more resistance to conventional tocolytic therapy, this condition should prompt the physician to use more aggressive perinatal assessment.