Detection of preterm labor by ambulatory monitoring of uterine activity for the management of oral tocolysis.

A study to evaluate whether ambulatory tocodynamometry at home could enhance the management of oral tocolysis was performed. On discharge from the hospital, after completing parenteral tocolysis, 60 patients received a lightweight tocodynamometer, designed for storage and transmission of uterine activity data. Sixty additional contemporary patients, who were matched for maternal age, parity, and risk factors, served as a control group. In addition to instructions regarding self-detection of recurrent preterm labor, monitored patients recorded uterine activity for greater than or equal to 200 min/day and then transmitted the data to the study center. Tocolytic dosage was adjusted to maintain mean uterine contraction frequency of less than 4/hr. Persistent uterine contractions of greater than or equal to 4/hr lead to in-hospital evaluation for recurrent preterm labor. The results indicate that the monitored group had a lower incidence of preterm births mostly because of a decrease in the proportion of patients with failed tocolysis. It is suggested that surveillance of uterine activity at home during oral treatment for preterm labor may be instrumental in improving perinatal outcome in high-risk patients.