Uterine activity and symptoms as predictors of preterm labor.

Women enrolled in a previously reported prospective trial of ambulatory tocodynamometry who developed preterm labor while using an ambulatory tocodynamometer were candidates for this analysis. Data from 51 women who met these entry criteria were evaluated and placed into four groups according to the initial reason for evaluation for preterm labor: monitored uterine activity, symptoms, both contractions and symptoms, or cervical examination at a routine office visit. Less than half (43%) had both subjective symptoms and an increase in monitored contraction frequency; 24% were initially identified by symptoms, 24% by uterine activity, and 10% at a routine office visit. We conclude that waiting for both an increase in uterine activity and subjective symptoms of labor will delay diagnosis in 50% or more of preterm labor patients and that women at risk of preterm birth should be evaluated promptly if either contractions or symptoms persist.