Lara C. Pullen, PhD

May 05, 2014

CHICAGO — The routine induction of pregnant obese women at 39 weeks of gestation can minimize stillbirths, caesarean deliveries, and delivery-related healthcare costs, a new computational model shows.

Approximately 27% of pregnant women in the United States are obese. "Complicating this issue is the fact that obese patients are at increased risk for caesarean sections," explained Lisa Gill, MD, from the Mayo Clinic in Rochester, Minnesota. And these "are not easy caesarean sections."

She and her colleague Michael Holbert, MD, also from the Mayo Clinic, designed a decision analysis model to compare the delivery and cost outcomes of pregnancies complicated by obesity.

She presented the results here at the American Congress of Obstetricians and Gynecologists (ACOG) 2014 Annual Clinical Meeting.

Obesity itself is a risk factor for stillbirth, and pregnant obese women also tend to have multiple comorbidities. In fact, obesity in pregnancy is actually its own comorbid condition, explained Dr. Gill.

The researchers created their computational model using existing data.

They estimated healthcare costs using known costs for vaginal and caesarean deliveries in 2008, and then translated these costs into 2013 dollars.

They also searched the literature to identify rates of spontaneous labor by gestational age. They used the data for all pregnant women to extrapolate a rate for obese women. In addition, they calculated the rate of caesarean delivery by week of gestation.

These data were woven into a predictive model. The results were based on a hypothetical cohort with routine induction for the women remaining pregnant at each gestational age.

The model predicted that 387 stillbirths would be avoided if obese women were induced at 39 weeks of gestation, as would 10,035 cesarean deliveries. And the savings in delivery-related healthcare costs would be $29.3 million.

"This is a really interesting idea," said Caela Miller, MD, assistant professor and gynecologic oncologist at the San Antonio Military Medical Center, who is a member of the ACOG Committee on Scientific Program.

"Now that the model has been created, it needs to be prospectively validated," she told Medscape Medical News.

Dr. Gill acknowledged that the study is limited by its computational nature and that, ultimately, a prospective trial is needed.

She reported that the randomized ARRIVE trial is being planned by researchers at the Eunice Kennedy Shriver National Institute of Child Health and Human Development to compare elective induction of labor at 39 weeks with expectant management.

Antenatal Testing

The risk associated with obesity during pregnancy is recognized by obstetricians at the Hospital of the University of Pennsylvania in Philadelphia.

At that hospital, all morbidly obese pregnant women undergo antenatal testing to determine whether the pregnancy is progressing satisfactorily and if the women should be induced.

In a poster presented here at the ACOG meeting, Paula Edelson, MD, and colleagues report that although it is still not known whether antenatal testing reduces the risk for stillbirth, the intervention does not appear to increase the risk for morbidity in these women.

"We are seeing so much morbid obesity, which is a huge problem," Dr. Edelson told Medscape Medical News, echoing a common theme at the meeting. "We are really relieved that we are not exposing these women to iatrogenic harm."

"After 39 weeks, it is acceptable to consider elective deliveries in patients who have large babies," said Raul Artal, MD, chair of the Department of Obstetrics, Gynecology, and Women's Health at Saint Louis University in St. Louis, Missouri. "And obese women are more prone to having large babies," he told Medscape Medical News.

Dr. Gill, Dr. Miller, Dr. Edelson, and Dr. Artal have disclosed no relevant financial relationships.

American Congress of Obstetricians and Gynecologists (ACOG) 2014 Annual Clinical Meeting: Abstracts 4S and 47S. Presented April 29, 2014.


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