Journal Issue: Low Birth Weight Volume 5 Number 1 Spring 1995
Home Uterine Activity Monitoring
Home uterine activity monitoring (HUAM) is a system of care that was introduced in an attempt to reduce the number of children born preterm. It couples use of a monitoring device with daily nursing contact by phone to provide support and advice as to when a woman should go to the hospital. Women attach an external tocodynamometer (a device strapped over the abdomen which senses uterine contractions and records their frequency) twice a day for one to two hours while lying down. The recordings are then transmitted via telephone to a central station.
If contractions are deemed excessive (usually four to six contractions per hour is considered the upper limit of acceptability), the woman is advised to seek medical care. The monitoring equipment has generally been shown to detect uterine contractions accurately; however, this premise was questioned at a recent meeting at the Food and Drug Administration.1 The approximate charge for the home uterine monitoring system is $90 to $100 per day. If the system is used between 24 and 36 weeks of gestation, the cost could easily exceed $7,000 for each pregnancy.2
It is thought that use of the monitor will help to identify an increase in contractions which are not perceived by the woman. The increase in unfelt contractions is thought to signal the very beginning of the process of preterm labor. Drug therapy aimed at stopping these contractions can then be given with the hope of preventing a preterm birth. It is not clear just how effective the monitors are in preventing preterm births because there have been no large-scale controlled scientific studies to determine their effectiveness.
Several studies of the monitor, which were conducted on a small number of women, concluded that it may be useful as an early warning system for preterm labor,3,4 but these studies have not determined whether the monitor or the daily nursing contacts that accompany it are responsible for the favorable results. Further studies have suggested that the daily nursing care was actually responsible for the improved birth outcomes, not the monitor.5,6 However, it appears that labor is detected slightly earlier if only the monitor is used.7 A recent review of this topic has indicated that all of the evaluations of this technology had serious methodologic deficiencies.8 Nonetheless, four of the five trials demonstrated no significant benefit from monitoring.
The American College of Obstetricians and Gynecologists recommends that home uterine activity monitoring devices remain investigational and not be routinely used.2 The College concluded that, until the efficacy of the technology has been established, home uterine activity monitoring should not be used clinically. In the future, HUAM may play a cost-saving role in preventing preterm birth in specific high-risk subgroups, such as in multiple pregnancies, but this role needs to be tested before being specifically advocated.