MODERN ANALYSIS OF PATHOLOGICAL UTERINE RINGS

A computerized medical record search of 61,406 live births from Januar y 1, 1990, through December 31, 1994, identified 14 cases of pathologi c uterine rings. This yielded an incidence of pathologic uterine rings of 0.02% of all live births. In a retrospective, matched study design , three control subjects having vaginal delivery and three having cesa rean delivery were matched with each case of pathologic uterine ring f or age, race, parity, estimated gestational age, single or multiple ge station, primary or repeat cesarean section, and indication for the ce sarean delivery. Comparison with controls who had cesarean section sho wed no significant differences in duration of labor, rupture of membra nes, use of oxytocin, or fetal head position. Pathologic uterine rings continue to occur in modern obstetrics, but their reported incidence has decreased. These data suggest that the characteristics of parturit ion have no clear association with the formation of a pathologic uteri ne ring.