How long is ‘normal’ labor?
Summary of a presentation by Leah Albers, CNM, DrPH ath the 46th ACNM Annual Meeting.
Leah Albers, CNM, DrPH, FACNM, is a Professor in the College of Nursing and Department of OB-GYN, School of Medicine at the University of New Mexico. She is the author of numerous articles in the Journal of Midwifery and Women’s Health as well as other journals.
When I got my program for the annual meeting, I highlighted, underlined, and put a star next to this educational session to make sure I would be there. Intuitively, I have known for years that “normal” labor does not normally follow the Friedman Curve. However, the Friedman norm is the one that is taught to most nurse-midwifery students and the one that many midwives are held to if they practice in hospitals, particularly academic medical centers. In our midwifery practice at Oregon Health Sciences University, between 30% and 40% of all the women we attend in labor get oxytocin for induction or augmentation. Can it be that over a third of women seen in a midwifery practice are not normal when it comes to labor, and need to be treated for their abnormality? It makes more sense to think that the norms may be faulty, not the women.
Leah Albers, CNM, DrPH, a midwife and clinical researcher at the University of New Mexico (UNM), looked at the length of labor in a 3-year consecutive sample of hospital births at UNM hospital. She restricted her sample to truly normal women with term pregnancies, spontaneous onset of labor, vertex singleton fetuses, and no medical problems. In addition, these women had unmedicated labors (no prostaglandins or oxytocin, no epidurals). They had normal vaginal births. Her sample included 1,473 women who met these criteria. (Friedman, when he developed his labor curves on a sample of 100 women, included women who did not meet these criteria, including women who had oxytocin augmentation of their labors.) When she looked at her data, Albers found the following:
Average (Mean) Length of Labor and One Standard Deviation – UNM Patients
|First stage (mean and SD)||Second stage (mean and SD)|
|Nulliparas||7.7 hr (5.9)||53 min (47)|
|Multiparas||5.7 hr (4.0)||17 min (20)|
When she looked at the mean, or average, labor and added 2 standard deviations to find the statistical limits of normal (that is, the longest labor that could be considered normal), she found that the UNM patients had a first stage with a normal limit that was twice that found by Friedman:
Statistical Limits – UNM Patients
|First stage (hour)||Second stage (minute)|
|Nulliparas||19.4 vs 8.5||147 vs 150|
|Multiparas||13.7 vs 7||57 vs 60|
Notice that the second stage of labor is about the same for Friedman’s women as for the women that Albers studied.
Worried that her study could be dismissed because it was done on a group of women in one hospital (who therefore tend to be more alike and maybe not so “average” as the women Friedman studied), Albers repeated her study with data from nine midwifery practices around the United States. In this second study, there were more differences represented in the women, racial and ethnic, urban and rural, old and young. They still had one thing in common – normal, unmedicated labors. In this larger study, the results were almost identical to those in the first study (the numbers in the table represent UNM, 9-site data, and Friedman in that order):
Statistical Limits ? Data from Nine Sites
|First stage (hour)||Second stage (min)|
|Nulliparas||19.4 / 17.5 / 8.5||147 / 147 / 150|
|Multiparas||13.7 / 13.8 / 7.0||57 / 64 / 60|
Albers did look at the complications in patients with “prolonged'”labor in her samples. The most common was postpartum hemorrhage, which occurred in 4.5% of patients at UNM, and in 6% of patients at the nine sites. Second was need for newborn resuscitation, which occurred in 4.2% of babies at UNM and 3.7% at the nine sites. Postpartum fever and five-minute Apgars less than 7 were seen in 1% of patients or less in both studies. Importantly, these complications occurred at the same rates in short, medium, long, and very long labors.
In summary, the normal progress in the first stage of labor in the patients that Albers studied was, on the average, half a centimeter an hour of cervical dilation less than half the rate that Friedman found. In the second stage of labor, Albers’ patients progressed at the same rate as Friedman’s.
How does Albers propose that midwives support the normal progress of labor that she found in her studies? She suggests information, reassurance, social support, mobility and position change, and hydration, techniques that stem from the midwifery model of care and that every midwife knows to be essential to a successful birth experience. Albers believes that using these common midwifery nterventions will avoid much over-treatment of laboring women and will result in safe, cost-effective care.
1. Albers LL, Schiff M, Gorwoda JG. The length of active labor in normal pregnancies. Obstet Gynecol 1996; 87:355-359.
2. Albers LL, for the CNM Data Group, 1996. The duration of labor in healthy women. Journal of Perinatology 1999; 19(2):114-119.
3. Friedman DA. The graphic analysis of labor. Am J Obstet Gynecol 1954; 68:1568-75.
For a related article on the length of normal labor, go to “How Long Is Labor, Anyway?”