Researchers found some women who received epidural
anesthesia during labor took more than two hours longer to deliver
their child, compared to women who didn't get the pain reliever.
"The effect of epidural can be longer than we think and as long as
the baby looks good and the women are making progress, we don't
necessarily have to intervene (and perform a Cesarean section) based
on the passage of time," Dr. Yvonne Cheng told Reuters Health.
She is the study's lead author and a specialist in maternal-fetal
medicine at the University of California, San Francisco.
Cesarean sections, or c-sections, are now used for about one of
every three births in the U.S., according to the Centers for Disease
Control and Prevention. That's about 50 percent more than in the
C-sections come with longer hospital stays and extra risks for
mothers and babies.
Cheng and her colleagues write in Obstetrics and Gynecology that two
common reasons for performing c-sections are that it appears labor
has slowed and that the baby is not progressing through the birth
Traditionally, doctors are taught that women who receive epidural
anesthesia will take about an extra hour to complete the second
stage of labor, which is the pushing part.
But the researchers write that it's unclear where the data for
what's considered a "normal" labor came from and that the extra hour
of labor is an average.
For the new study, they compared data from over 42,000 women who
delivered their children at the University of California, San
Francisco between 1976 and 2008. About half of the women received
epidural anesthesia and the other half did not.
Specifically, the researchers were looking at the length of the
second stage of labor at the 95th percentile, which is an extreme.
That means 19 out of 20 women would complete that stage of labor
within that time.
For women who had never had a child before and were in the 95th
percentile for length of labor, the second stage took about three
hours and 20 minutes to complete without anesthesia and five hours
and 40 minutes with the shot.
Women who previously had a child, who usually have shorter labors to
begin with, took about an hour and 20 minutes to complete the second
stage of labor without anesthesia at the 95th percentile. That
compared to four hours and 15 minutes with an epidural.
Overall, the researchers found the second stage of labor took about
two hours longer at the 95th percentile when women got an epidural.
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For women who have a more typical delivery, the epidural probably
adds less time, Dr. Karin Fox said. "It's probably difficult to know
for each individual patient," she told Reuters Health.
Fox is a specialist in maternal-fetal medicine at the Baylor
College of Medicine and Texas Children's Hospital in Houston. She
was not involved with the study.
While she said the results are not surprising, there may be reasons
besides the epidural why some women's labors last longer.
She also said women shouldn't stay away from epidural anesthesia
just because it will prolong labor. "There are many reasons for
having an epidural," she said.
Dr. Christopher Glantz cautioned that although the health of babies
in the epidural and non-epidural groups was similar, mothers tended
to have more complications if they had longer labors.
Glantz was not involved with the study but is a high-risk
pregnancy specialist at the University of Rochester Medical Center
in New York.
"It would appear that the upper limit of what can be tolerated is
greater than what was previously thought, which takes away some of
the impetus to intervene (with c-section) in what appears to be a
premature fashion," he said.
Cheng and her colleagues write that while doctors should not only
rely on this paper to establish how long labors may last, these
findings and previous research suggest current definitions are not
"All the experts in the field should get together to look at the
evidence that's out there and come up with informed definitions,"
Obstetrics and Gynecology, online Feb. 5, 2014.
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