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The number of women who gave birth vaginally after a Caesarean delivery has dropped in recent years, but without the expected reduction in infant and maternal death rates, a new study has found.
Women who deliver vaginally after having a previous C-section face small but real health risks, such as uterine rupture. So as the number of vaginal births after Caesarean sections declined, it would have seemed that infant and maternal death rates would have fallen, too, says study leader Dr. John Zweifler, chief of the University of California, San Francisco-Fresno Family and Community Medicine Department.
Zweifler and his colleagues examined birth data in California from 1996 through 2002, before and after a 1999 guideline to reduce vaginal births after Caesarean sections was adopted. The guideline, issued by the American College of Obstetricians and Gynecologists, requires a physician to be immediately available in the hospital to perform emergency care for a woman attempting vaginal birth after a prior Caesarean section, in case of complications such as uterine rupture.
Because that's not always possible, especially at smaller hospitals, the vaginal births after Caesarean sections rate was expected to decline.
The researchers found 386,232 California women who had given birth by C-section. About 75,000 attempted a subsequent vaginal delivery, while the other 311,000 had a repeat C-section. Of those who attempted a vaginal birth after a C-section, more than 61,000 were successful.
The study authors found that attempted vaginal births after a C-section dropped from 24 percent before the guidelines to 13.5 percent after the guidelines. Women who gave birth to low birth-weight babies -- less than 1,500 grams, or 3.3 pounds -- had higher newborn death rates with vaginal birth delivery after Caesarean section than with a C-section, Zweifler says.
But women giving birth to infants of normal weight -- at or above 3.3 pounds -- had similar newborn and mother mortality rates, regardless of whether it was vaginal birth after a C-section or a repeat C-section, the researchers found.
For instance, for newborns weighing 5.5 pounds to less than 8.8 pounds, "there were 0.3 deaths per 10,000 live births before the guidelines (with attempted vaginal birth after C-section), Zweifler says. "After the guidelines, there were 0.4" per 10,000 live births.
For women undergoing repeat C-sections for children of normal weight, there were 0.4 deaths per 10,000 live births before the guidelines, and 0.3 deaths afterward, the researchers reported.
Similarly, maternal death rates per 100,000 live births for attempted virginal birth after Caesarean deliveries were pretty much the same for both periods -- two for the years 1996 to 1999, and 8.5 from 2000 to 2002. For repeat C-sections, the maternal death rates per 100,000 births were 8.7 from 1996 to 1999, and 11.9 from 2000 to 2002.
The study findings appear in the May-June issue of the Annals of Family Medicine.
The 1999 guidelines were issued due to safety concerns and medical and legal considerations, the researchers said.
In the United States, babies born by C-section increased from 4.5 percent in 1965 to 26.1 percent in 2002, with nearly 40 percent of the births repeat C-sections. Vaginal births after a C-section increased from 1 percent in 1974 to 27.4 percent in 1997, then back down to 12 percent in 2002, the researchers said.
In an accompanying essay, Dr. Lawrence Leeman, a physician who specializes in family medicine, obstetrics and gynecology at the University of New Mexico, says preserving a woman's childbirth options means preserving her right to a vaginal birth after a Caesarean section, as well as a C-section.
Dr. Richard Frieder, an obstetrician-gynecologist at Santa Monica-UCLA Medical Center and a clinical instructor of obstetrics and gynecology at the David Geffen School of Medicine at the University of California, Los Angeles, says the new study has a major flaw.
"It doesn't address maternal or fetal complications," he says.
"The study took birth certificates, and all they did was add up numbers of who lived and who died in terms of infant mortality and maternal mortality.
"The main complication of vaginal births after Caesareans is not death but morbidity, such as blood transfusions, hysterectomy, infection, heart attack, stroke, kidney failure, the baby having low Apgar scores or brain hemorrhage," Frieder adds. "All they are talking about is how many people lived or died. But they didn't measure complications.
"If they had looked at complication rates, there would have been a huge difference favoring C-section."
Complications weren't considered, Zweifler says, because the only information the researchers had access to was from birth certificates, which don't list complications.
(The HealthDay Web site can be viewed at www.HealthDay.com.)
c.2006 HealthDay News
