Prevention of preterm birth by ambulatory assessment of uterine activity: a randomized study.

Tocodynamometry, used on an ambulatory basis, has been shown to detect uterine activity. The objective of this study was to assess the effectiveness of ambulatory tocodynamometry in the early identification of preterm labor. In this investigation 67 women at risk for preterm labor were randomly divided into two groups: 34 received a uterine activity monitor while 33 patients used palpation. Approximately two thirds of the study sample developed preterm labor. Upon diagnosis of preterm labor, parturients in the control group had cervical dilatation of less than 3 cm (p less than 0.001) and effacement of greater than 50% more often than the monitored group (p less than 0.01). As a result there was a significant decrease in the number of patients who responded to tocolytic therapy in the unmonitored group. Among those with preterm labor the time gained in utero was greater in the monitored group (8.2 +/- 2.7 weeks) compared to the control group (4.2 +/- 2.9 weeks) (p less than 0.05). Subsequently 29 of 34 monitored patients attained term (36 completed gestational weeks) versus only 18 of the 33 patients in the unmonitored group (p less than 0.01). Although the sample size is relatively small, uterine activity monitoring in these very high risk patients resulted in an increased number of suitable candidates for tocolysis and allowed a significantly greater percentage of women to reach term.