Variability in Rate of Cervical Dilation in Nulliparous Women at Term

Abstract

In our setting, the rate of labor in nulliparous women at term was highly variable, and it did not appear to be affected by cervical dilation on admission.

Perils of the new labor management guidelines

“…The combined effect of these biases probably explains in part their finding that the rate of active-phase dilatation increases exponentially, rather than linearly as Friedman and many others have previously found. [6][7][8][9][10][25][26][27][28][29][30][31][35][36][37][38][39][40][41][42][43][44][45][46] Transition to active phase One critically important way in which the new guidelines depart from the old is in identifying the transition from latent to active phase during the first stage. It is widely, but erroneously, concluded from the Friedman dilatation curve that the active phase of labor begins at 4 cm.…”

“…In fact, numerous studies done in different parts of the world over the course of several decades confirmed the basic nature of the original curves, and validated their usefulness in clinical practice. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] There have been disagreements over the importance of the latent phase or even the existence of the deceleration phase of dilatation, but the core finding that active-phase cervical dilatation progresses linearly, with a lower limit of normal approximately 1.0 cm/h in nulliparas, has been remarkably consistent among studies. It is also noteworthy that in many institutions the introduction of labor curves to clinical care was associated with a decline in the cesarean rate.…”

“…The presence of the deceleration phase has been confirmed by others. 43,49,60,[80][81][82][83] Despite the artificial nature of the deceleration phase of the dilatation curve, it reflects a critically important time in labor. Deceleration generally marks the beginning of fetal descent, and its prolongation portends significant problems for the labor.…”

Physiologic partograph to improve birth safety and outcomes among low-risk, nulliparous women with spontaneous labor onset

“…Moreover, receiving oxytocin at an earlier stage of labor is associated with a higher cesarean risk (5). The cesarean rate following early labor admission in this low-risk population is reported to be more than twice as high as the reference group rate in most studies (1–5) although an Italian team recently reported no difference in cesarean rates between women presenting at ≤ 4 cm or > 4 cm (35). Cesareans for dystocia were higher in the early admission groups in both identified studies reporting specific surgical indications (p < 0.001 in each study) (1,4).…”

“…Women admitted early (e.g., < 4 cm dilatation) are approximately twice as likely to be augmented with oxytocin when compared to women admitted in more active labor (1,2,34). Indeed, the rate of oxytocin use is inversely related to cervical dilatation at admission (r = −0.79, p < 0.05) (35). Moreover, receiving oxytocin at an earlier stage of labor is associated with a higher cesarean risk (5).…”