"Does 4 cm dilation constitute active labor?" interview with Dr. Emanuel A. Friedman

Emanuel A. Friedman M.D., of Columbia University, introduced the labor curve, commonly known as “Friedman’s Curve ” to depict the average amount of time it took for a labor patient to dilate each cm. Published nearly 60 years ago, the curve is still followed by a majority healthcare providers to define normal labor.

In 2012, when the National Institute of Child Health and Human Development (NICHD), the Society for Maternal and Fetal Medicine (SMFM), and ACOG held a workshop aimed at “preventing the first Cesarean.” In the workshop, it was discussed that many cesarean sections are simply performed because many women are wrongly categorized as “ failure to progress” based on Friedman’s Curve.

In 2014, ACOG and SMFM issued a consensus statement “Safe Prevention of the PrimaryCesarean Delivery ” to bring down the rising cesarean section rates. The statement redefined normal and abnormal labor and stated that Friedman’s Curve should no longer be used as the basis for modern labor management (ACOG 2014).

A critical study published by Zhang et al. formed the basis of the new guidelines. The study was based on data from the Consortium on Safe Labor and looked at labor records of 62,000 women from 19 hospitals across the U.S. The researchers concluded that “ failure to progress” should be diagnosed at 6 cm and not 4 cm as stated earlier.

ACOG also reaffirmed this statement in 2017 and again in 2018 ACOG Committee Opinion No.766: Approaches to Limit Intervention During Labor and Birth.

Here is an interview with Emanuel A. Friedman about definitions of active and in active labor. He opines that “Woman describes her own labor curve, it is irrelevant to designate a particular point in labor as a demarcation between active and in active labor.”