A pregnant woman lies in a hospital bed and holds onto her belly as she prepares for labor.
Researchers in 2012 relaxed the parameters that define labor stages, providing moms more time to give birth without the need for a C-section. (For Spectrum Health Beat)

Let’s jump right in with a simple fact of nature: Labor is a means to an end. It is the process your body must go through for your baby to be born after about 40 weeks of gestation.

In reality, of course, labor can be much more complicated and involved.

It’s always work, but it’s always doable work. And it’s quite an emotional high when you get that little one in your arms.

We can divide labor into three distinct stages, starting at initial dilation of the cervix and concluding with delivery of the placenta.

The first stage begins at dilation and lasts until the woman reaches 10 centimeters. This stage is also broken down into phases—early, active and transition.

The early phase starts at dilation and lasts to about 6 centimeters. The active phase is 6 to 8 centimeters and the transition phase is 8 to 10 centimeters.

These numbers changed a few years ago when the American College of Obstetricians and Gynecology began seeking to lower the rate of cesarean sections in first-time deliveries.

But back to the stages.

The second stage of labor lasts from complete dilation—that is, 10 centimeters—to the birth of the baby.

The third stage is delivery of the placenta, which can take up to 30 minutes after birth.

Historically, the division of labor came from studies done by Emanuel Friedman, a doctor in the 1950s.

Friedman’s curve

In 1955, Dr. Friedman plotted a graph based on observations he made of 500 women at one hospital.

Because he took the time to graph out the data averages on a chart, his findings became known as Friedman’s curve. Obstetrics practitioners have followed this principle for many years.

The 500 mothers in Dr. Friedman’s study were all first-time moms, about 70% of them between the ages of 20 and 30. Less than 2% had given birth by C-section.

In graphing out the data, Dr. Friedman called it active labor at 4 centimeters because dilation started moving faster at that point.

In 2002, a study in Journal Watch found that dilation in the active phase was much slower than what had been found in the Friedman curve. The study involved more than 1,300 women who gave birth from 1992 to 1996.

The study authors found “the Friedman curve likely represents an ideal, rather than an average, curve.”

Additional studies have followed.

One, involving more than 62,000 women in 19 U.S. hospitals, showed the average rate of dilation had been much slower than observed in Friedman’s curve.

Around 2012, the American College of Obstetricians and Gynecology and other organizations redefined some of the labor terms and said Friedman’s curve should not be used.

Examining various studies and sets of data, they opted to change the parameters—the active labor phase would begin at 6 centimeters.

The fact is, most women don’t progress as quickly as the women involved in the Friedman study.

By setting the marker at 6 centimeters, providers wouldn’t feel the pressure to perform a C-section because of failure to progress.

This is an important point for many mamas-to-be, as they often tell me they’d like to see if they can have a natural birth, even if it goes long. Quite frequently, the answer is yes.

Finding a care team who will safely support your wishes—whatever they may be—is key.

Relax—and labor on

Why were Friedman’s dilations different? There’s a number of suspected reasons. Medications then are different then medications now. Newborn weights are heavier now. Moms also have higher body mass index.

What Dr. Friedman thought had been slow labor progress, researchers now believe is normal.

A 2016 study involving about 420 women in Italy supports this notion. Half were assigned to follow the Friedman curve, the other half followed the more “relaxed” model reflected in the 2014 changes.

The women evaluated according to the Friedman curve had twice the C-section rate as the latter group.

What does this mean? Labor can and often does take its good-old, sweet time.

For a first-time mom, it can take quite a while.

And that’s OK.

In the childbirth classes I teach, early (latent) labor can last up to 12 hours on average. Active labor can last six or more hours and the transition phase can last a few minutes to a few hours.

So there’s really just one thing to remember: Relax and let your body do its thing.