Measuring the electrical activity of the uterus from the surface of the mother’s abdomen, a procedure referred to as electrohysterography, more accurately detects the occurrence and length of contractions in obese women in labor than conventional monitoring does, Florida researchers report.

In a study published in the journal Obstetrics and Gynecology, Dr. Tammy Y. Euliano at the University of Florida, Gainesville, and colleagues compared electrohysterography with tocodynamometry and intrauterine catheter pressure monitoring to see which method is best for detecting contractions in obese women. The study included 25 women with a body index of at least 34 (a body mass index higher than 30 is considered to be obese.)

The team was not able to collect tocodynamometry, intrauterine pressure, and electrohysterography data simultaneously. In paired comparisons, “tocodynamometry identified 248 contractions compared with 336 by electrohysterography, whereas intrauterine pressure catheter monitoring identified 319 contractions,” the investigators report.

The electrohysterogram findings correlated better with those of the intrauterine pressure catheter, than with tocodynamometry, Euliano’s team found.

However, the physicians point out that intrauterine pressure catheter placement is an invasive procedure, increasing the risk of infection, perforation of the uterus, and rupture of the placenta.

The investigators conclude that electrohysterography may provide a better way to noninvasively monitor uterine activity, especially in obese women.

“There is no specific degree” of obesity for which the clinician would opt for intrauterine pressure monitoring, Euliano told Reuters Health. “We first try external monitoring, and only use intrauterine pressure when that is inadequate” or if there is another reason to use it.

SOURCE: Obstetrics and Gynecology May, 2007.