February 7, 2014 — A new study suggests clinicians should give many women more time to progress in labor before considering a caesarean section, forceps or other interventions, the New York Times reports. The study focused on the second stage of labor, when women "push," according to the Times.
Current guidelines from the American Congress of Obstetricians and Gynecologists define the second stage of labor as abnormally long during a first birth if it exceeds three hours for women who have received an epidural or two hours for women who have not had an epidural.
For the new study, published on Wednesday in Obstetrics & Gynecology, researchers at the University of California-San Francisco analyzed data on 42,268 women who delivered vaginally without problems between 1976 and 2008. About half of the women received epidurals during labor.
The researchers compared the average time that women who had received epidurals were in their second stage of labor with that for women who did not receive epidurals. They also looked at the upper limits of labor durations for both groups of women. The study found that a normal second stage of labor during a first birth can take as long as 3.3 hours for women who do not receive epidurals and as long as 5.6 hours for women who do receive epidurals. For women who have given birth before, the second stage can be as long as 1.35 hours without an epidural and 4.25 hours with one.
Overall, 31% of first births and 19% of subsequent births in the study would have been considered abnormally long under ACOG's guidelines.
The study also found that birth trauma to the infant, such as bruising, was more common among women with prolonged second stages, although the newborns' scores on physical health tests and admissions to intensive care were not affected. There also was a higher risk of perineal lacerations and postpartum hemorrhage among women with prolonged second stages.
The Times notes that the findings are part of a growing body of evidence showing that a normal second stage of labor is longer than it was in past decades.
Several experts, including study lead author Yvonne Cheng, an associate professor of obstetrics and gynecology at UCSF, told the Times that the guidelines should be adjusted accordingly.
Jeffrey Ecker, chair of the committee on obstetrics practice for ACOG, did not say whether a revision is being considered but noted, "Often what's best and most appropriate -- and most difficult -- during labor is patience."
Katherine Laughon, an investigator at the NIH who was not involved in the study, said it shows that "clinicians might need to wait later before intervening with oxytocin, forceps, vacuum or a cesarean." However, she noted that "clinicians and women need to balance benefits of vaginal delivery with potential increases in risk for mom and baby" (Saint Louis, New York Times, 2/5).