Fetal oximetry clarifies need for surgical deliveries. (Not Endorsed by ACOG).

CANCUN, MEXICO -- Intrapartum monitoring of fetal oxygenation by pulse oximetry is a valuable tool that may help obstetricians avoid malpractice suits and lead them to do surgical deliveries for the right reason, Dr. Frank H. Boehm said.

"I was a skeptic, but I've found fetal pulse oximetry to be very user friendly and a wonderful adjunct that gives us extra information," Dr. Boehm said at a conference on obstetrics, gynecology, perinatal medicine, neonatology, and the law.

Dr. Boehm, director of the division of maternal/fetal medicine at Vanderbilt University in Nashville, Tenn., was a coinvestigator in the major U.S. study of fetal pulse oximetry. He has no financial relationship with the company that makes the oximetry device, Nellcor.

The American College of Obstetricians and Gynecologists has so far not endorsed fetal pulse oximetry for routine intrapartum use, in large part because the major US. trial of the technique failed to show that it cut the rate of operative deliveries, Dr. Boehm said.

In the multicenter trial, which involved 1,010 pregnancies, use of oximetry dropped the rate of cesarean sections because of a nonreassuring fetal status from 10.2% in control deliveries to 4.5% when oximetry was used. But oximetry use was also associated with a 19% rate of operative deliveries because of shoulder dystocia, up from the 9% rate in the control group. This unexpected rise meant that the overall rate of cesarean deliveries was 29% with pulse oximetry and 26% in the control group.

Recent analyses have helped clarify why the rate of cesarean deliveries for shoulder dystocia increased in the study. Dystocia appears to trigger fetal heart rate abnormalities. Squeezing a fetus through a tight pelvic opening appears to cause vagal nerve stimulation that leads to variations in fetal heart rate.

In the multicenter trial, when a fetus had heart rate abnormalities ...