FRIDAY, March 30, 2012 (HealthDay News) -- American women today are spending about two hours more in labor during childbirth than women did 50 years ago, a new report says.
The report's authors said several factors helped to explain the longer labors.
"Older maternal age and increased BMI (body-mass index, a ratio of weight to height) accounted for a part of the increase. We believe that some aspects of delivery-room practice are also responsible for this increase," lead author Dr. Katherine Laughon, an epidemiologist with the Eunice Kennedy Shriver National Institute of Child Health and Human Development, said during a Friday afternoon news conference.
For the study, Laughon's team collected data on nearly 40,000 women who gave birth between 1959 and 1966, and compared those findings with nearly 100,000 women who delivered between 2002 and 2008.
The researchers found women in the 21st century were in labor 2.6 hours longer for first births and two hours longer for subsequent births than women from the 1960s.
Mothers in the 2000s also were older, heavier and used painkillers more during labor, and were more likely to have a Cesarean delivery than women in the 1960s.
Other differences that might explain the increase reflect changes in later-stage delivery practices. For instance, in the 1960s the use of episiotomy (a surgical incision to enlarge the vaginal opening during delivery) and forceps (surgical instruments used to extract a baby) were more common, the researchers noted.
The use of epidural injections to ease the pain of delivery is more common now than 50 years ago. Epidurals were used in more than half of recent deliveries, compared with 4 percent of deliveries in the 1960s, the study authors said, adding that epidural anesthesia is known to increase delivery time.
The study also found that Cesarean deliveries are four times more common today than 50 years ago -- 12 percent vs. 3 percent.
"Women are in labor longer [today] because they are admitted [to the hospital] earlier," said Dr. Michael Cabbad, chairman of obstetrics/gynecology and chief of maternal/fetal medicine at the Brooklyn Hospital Center in New York City. "There is a tendency for women to come to the hospital in an earlier phase of labor because of fear of arriving too late."
When a women is admitted today, she is started on intravenous fluids and put in a bed, which slows down the labor process, Cabbad added.
The new report appears in the March 10 online edition of the American Journal of Obstetrics and Gynecology.
For more on childbirth, visit the U.S. National Library of Medicine.