When a pregnant woman is in labor, the wait for "10" — the number of centimeters the cervix must be dilated before the baby can be born without intervention — can feel like forever.
In reality, the amount of time a woman experiences “normal” labor may be a lot longer than previously assumed, recent research by an international team of experts shows.
For decades, doctors have depended on a paper from the 1950s that suggested that women experiencing normal labor should dilate at a rate of 1 centimeter (cm) an hour. Doctors often declare "failure of labor to progress" if woman's cervix is dilating at a slower rate than the "norm."
Women having their first baby tend to be the slowest — taking up to seven hours to make it from 4 cm to 5 cm dilation and over three hours to progress from 5 cm to 6 cm.
The time it takes for a woman to deliver her baby is crucial: In a slow delivery, doctors may assume it’s a sign something is going wrong and suggest either medication to speed up labor or a cesarean section.
It's perfectly normal for the duration and the rate of progression of labor to vary from woman to woman, said the study's lead author, Dr. Olufemi T. Oladapo, medical officer at the World Health Organization’s department of reproductive health and research.
"While on average some women could dilate at 1 cm per hour, or even faster, others might dilate slower than this and still deliver a healthy baby without any complications," he explained.
"When there is no other labor problem other than the cervical dilation rate slower than 1 cm per hour — when all vitals and other labor observations of mother and unborn baby are OK," doctors should consider supporting the mother rather than rush to expedite delivery, Oladapo said.
When labor feels stalled for 'hours and hours'
C-section rates have been rising worldwide, the researchers explained in the report published in January. In the US, rates have been declining since 2007, but still one-third of births, or 1.2 million babies, were delivered by c-section in 2015, the latest year for which the Centers for Disease Control and Prevention has data.
As part of the WHO’s Better Outcomes in Labor Difficulty, the researchers took a close look at the patterns of labor progression in 5,607 women in Nigeria and Uganda who gave birth vaginally and who had no adverse outcomes.
They found that first-time moms could take as long as 24 hours to go from 3 cm to 10 cm, which is when the second stage of labor starts. Added on to that could be as much as three hours before the baby was born.
The research's findings could likely apply to women around the world, as well. Doctors at some institutions have recognized over the years that many women progressed at a different rate and still had healthy babies, said Dr. John Fisch, director of Womancare Associates and an associate clinical professor in the department of obstetrics and gynecology at Magee-Women's Hospital at the University of Pittsburgh Medical Center.
“It’s nice to have some studies now to back that up,” Fisch said. Sometimes it can look as if labor has stalled out for "hours and hours."
Many OB-GYNs learned in medical school that women should be offered a c-section if they weren’t progressing as fast as that 1950s paper said they should, Fisch said.
“What we do know now is that many, many c-sections are done too soon,” Fisch said. “That’s especially true before they reach 6 centimeters.”
At Magee-Womens Hospital, “we preach patience," Fisch said.
Is it safe to wait?
There are reasons to try to avoid a c-section: the surgery comes with risks.
"“Hemorrhage and infection are by far the two most common complications with cesarean sections," Fisch said. "Less common complications include injury to the bladder or surrounding tissue. While these are also risks from vaginal delivery, they are more common with cesarean sections.”
Women and their doctors are usually on the same page, Fisch said. But, if your doctor wants you to have a c-section and you'd rather hold off, there are a couple of questions Fisch suggests you ask: “Is it safe for me and the baby to give it more time?” and “What are the risks for waiting?”