The Friedman Curve: An Obsolete Approach to Labor Assessment

These researchers concluded that the Friedman curve likely represents an ideal, rather than an average, curve.

The Friedman curve, the gold standard for rates of cervical dilation and fetal descent during active labor, was developed almost 50 years ago. To define a modern curve for normal labor, these researchers evaluated data on 1329 nulliparous, full-term women with spontaneous labors and vertex presentations who gave birth to singletons of normal birth weight from 1992 to 1996.

Dilation in the active phase was much slower on the modern curve than on the Friedman curve (mean time from 4 cm to complete dilation, 5.5 vs. 2.5 hours). Among the current study's patients, labor lasting more than 2 hours without apparent change was not uncommon before 7 cm of dilation. Friedman described 3 stages in the active phase: acceleration, maximal slope, and dece…

Reviewing Author

Ann J. Davis, MD