December 12, 1997

Seminar spotlights latest in high-risk obstetrics

Seminar spotlights latest in high-risk obstetrics

A new fetal monitoring technique and the diagnosis and treatment of gestational diabetes were two of many topics covered during last week's 23rd Annual High-Risk Obstetrics Seminar held at Vanderbilt University Medical Center.

The two-day conference was attended by more than 450 physicians and nurses who work with high risk pregnancies. Although most of those attending were from Tennessee, many came from across the United States.

Dr. Gary A. Dildy, of the Department of Obstetrics and Gynecology at the University of Utah Medical Center, is one of several researchers across the country testing a new way of assessing the status of a fetus during labor, and he shared some of his preliminary findings with the group.

The technique, called Fetal Oxygen Saturation Monitoring, is also being studied at VUMC and is used in cases of "nonreassuring fetal heart rate tracings," or decelerations in the fetus' heart rate that may indicate decreased oxygen delivery (hypoxia) in the fetus.

Use of the technique may help eliminate unnecessary Caesarean sections by removing some of the guess work about fetal status, Dildy told the group. When using routine electronic fetal heart rate monitoring, it can only be assumed that decelerations in the heart rate or changes in heart rate variability are due to poor oxygen saturation. The Caesarean section rate has risen steadily over the past 35 years, Dildy said.

In 1960, before electronic fetal heart rate monitoring was introduced, the Caesarean rate was less than five percent, Dildy said. In the 1980s, the rate rose to around 24 percent and has shown a slight decline recently to about 22 percent. With four million deliveries each year, about one-third of the Caesarean performed are due to hypoxia, Dildy said. Many could possibly be eliminated if a more accurate assessment, like pulse oximetry, becomes routine.

With the monitoring technique, a sterile, single-use pliable device is inserted into the mother and rests next to the cheek or temple of the fetus during labor. It measures the oxygen saturation level of the infant, which is adequate if it is greater than 30 percent.

The multi-center study of the technique will be completed in 1998.

Dr. Cornelia R. Graves, assistant professor of Obstetrics and Gynecology, and medical director of Critical Care Obstetrics at VUMC, spoke about gestational diabetes at the conference. Gestational diabetes complicates 3 to 5 percent of all pregnancies.

Graves said that health care providers should begin screening expectant mothers for risk factors for diabetes on the first prenatal visit. All women should be formally screened by 24 to 28 weeks of pregnancy.

Risk factors include obesity, a family history of diabetes and hypertension during pregnancy, and previously having a large infant.

Other topics at the conference included reducing the incidence of Caesarean section and managing preterm labor in a managed care environment.