Re: BMI May Predict C-Section Risk
From: J. Hellriegel (jhellrie@pce.net)
Wed Oct 13 11:10:36 1999
Does BMI predict size of baby, size of pelvis?
--
At Wed, 13 Oct 1999, Geffrey Klein, MD wrote:
>
>Tuesday October 12 7:05 PM ET
>
> BMI May Predict C-Section Risk
>
> By SUSAN PARROTT Associated Press Writer
>
> DALLAS (AP) - Though doctors have long known that obese women have
>difficult pregnancies, a pregnant woman's risk for a Caesarean section can
>now be predicted by determining her body mass index, a ratio of weight to
>height.
>
> Knowing a patient's BMI would allow an anesthesiologist to prepare early
>and more safely for the possibility of an emergency Caesarean, according to
>researchers who presented the study Tuesday at the annual meeting of the
>American Society of Anesthesiologists.
>
> In the general population, a BMI of 30 or more is considered obese -
>roughly a person who is 5-feet-1 and weighs 158 pounds. No BMI standards
>have been set for pregnant women.
>
> A survey of 2,500 women who delivered babies at Duke Medical Center found
>that mothers who had C-sections had an average BMI of 53 at the time of
>delivery, compared to a BMI of 31 for those who had vaginal deliveries.
>
> While the BMI varied greatly, the average weight of patients ranged only
>from 191 pounds for patients that had C-sections to 182 for those with
>normal deliveries.
>
> ``Weight is not the best description of obesity. Tall people can weigh
>more than short people without being obese,'' she said.
>
> Those with a BMI of 40 or more at the time of delivery are considered at
>greatest risk for Caesareans, said lead researcher Dr. Elizabeth Bell.
>
> Knowing there was a greater risk would allow an anesthesiologist to
>prepare for an emergency C-section by inserting an epidural catheter into
>the patient's back so regional anesthesia could be administered quickly.
>Regional anesthesia generally is considered safer than general anesthesia
>for obese women, whose airways can become obstructed by excess fat tissue.
>
> Overweight pregnant women are at greater risk of gestational diabetes and
>tend to have larger babies. Fat tissue also can hinder the baby's ability
>to pass through the birth canal, Bell said.
>
> The study found that 98 percent of women with a BMI of 60 or greater had a
>C-section, while none of the women with a BMI of 20 or less had a
>C-section.
>
> The rate was 0.3 percent for women with a BMI of 21 to 30, 32 percent with
>a BMI of 31 to 40, 78 percent with a BMI of 41 to 50, and 94 percent with a
>BMI of 51 to 60.
>
> Of the 2,500 deliveries studied, about one-third, or 833, were C-sections.
>
> Body mass index gives obstetricians another tool, though doctors already
>knew that overweight women have more difficult deliveries, said Dr. Ron
>Ramus, who was not involved in the study.
>
> About 20 to 25 percent of U.S. pregnancies end up in Caesarean sections,
>said Ramus, the assistant professor of obstetrics and gynecology at the
>University of Texas Southwestern Medical Center.
>
> Ramus said that doctors don't recommend dieting for pregnant women but
>those already overweight should be careful not to gain even more weight
>during pregnancy.
>
> In another study released Tuesday, researchers found that the percentage
>of women getting regional anesthesia during childbirth has tripled since
>1981 at the nation's busiest hospitals, and quadrupled at small and midsize
>hospitals.
>
> Epidurals and spinal analgesia were received by 66 percent of women who
>delivered in 1997 at hospitals with at least 1,500 deliveries a year, up
>from 55 percent in 1992 and 22 percent in 1981.
>
> Researchers from the University of Colorado School of Medicine in Denver
>studied 750 U.S. hospitals. They attributed the increase to better drugs
>and new technology.
--
John Hellriegel, Jr., MD, PhD
