Take a look at these screen shots, all taken from various pregnancy related sites marketed towards pregnant people within 5 minutes of each other. Notice anything? Can you tell me, based on this information, when exactly early labor becomes active labor?
It’s a bit of a hot mess, isn’t it? There’s a reason for all this confusion!
When early obstetricians first set out to describe and define labor as a set of stages and phases, they basically divvied up the first stage of labor into roughly equal parts. Early labor was the first third (1-3 cm), Active Labor was the second third (4-6 cm) and Transition was the final third (7-10 cm). These divisions stuck around for decades. Eventually doctors formed professional organizations, which worked to bring some standards to the profession, including practice guidelines. And the practice guidelines for active labor said that if the cervix wasn’t dilating at least 1 cm per hour in the active phase, something was wrong and the doctor should consider doing a cesarean.
In 2011, with the cesarean rate approaching a third of all births, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine got together to take a hard look at all this and see if there was something they could do about it. In 2014, they came out with a joint statement on the Safe Prevention of the Primary Cesarean Delivery. In this document, they outlined several recommended changes, things like more patience with prolonged pushing, reducing inductions before the EDD, and using doulas. The most striking change they made was they changed the definitions of the phases of the first stage of labor.
The statement itself just says that active labor should start when the cervix reaches 6 cm. Some people interpreted this as 6 cm is still early labor. Some (including me) read that as 6 cm as the start of active labor. It didn’t change anything about the other phases, but most places have interpreted the revised chart to be something like this, just dividing the remaining phases evenly:
Let’s be clear: actual human physiology did not change because these doctors voted to change the definition. The change was made to change the way people looked at what was happening. So previously if someone in labor remained at 5 cm for over an hour, it might have been considered “stalled labor” and a cause for cesarean. Now, since the standard for active labor doesn’t apply, that (surprisingly common) plateau at 5 cm is normal.
This seems to be working, at least a little. There was a minor downturn in cesarean rates in the years after the change. How it plays out long term remains to be seen.
Next week I’ll address an unintended side effect I’ve seen from this change and how you can navigate that in your birth.