Objective: To describe the time relation between symptoms, contractions, and the clinical diagnosis of preterm labor.
Methods: We analyzed the records from 57 women who were enrolled in a previously reported trial of home uterine monitoring and who developed preterm labor while using the monitor. In a post hoc descriptive study of signs and symptoms during the 7 days preceding a diagnosis of preterm labor, we reviewed uterine contraction records and study records of the responses to a standard list of questions about potential symptoms of preterm labor.
Results: Monitored contraction frequency increased on the day of preterm labor diagnosis, from an average of fewer than three per hour to five per hour, but was not increased on any of the days before the day of diagnosis. Neither symptoms nor contraction monitoring strips indicated any significant changes more than 24 hours before the clinical diagnosis was made. Self-palpated and monitored contractions were the most common symptoms of preterm labor.
Conclusion: A clinical diagnosis of preterm labor is preceded by an increase in self-palpated and monitored contractions and other symptoms for less than 24 hours.