“A revision of existing active labor expectations . . . is warranted, and efforts to do so must supersede efforts to change labor to fit existing expectations.”
Neal 2010, p. 31713
“How long is normal labor?” is a crucial question because doctors determine when to intervene based on when they think labor duration has exceeded normal range, and many doctors think labor doesn’t take as long as it actually does.
In this blog post, we’ll answer that question and then explore the ramifications of the mismatch. Here’s the plan: First, we’ll look at how labor progress standards came to be set that don’t reflect normal ranges and at the research establishing what those normal ranges really are. Next, we’ll see what’s happened since more accurate data has become available. After that, we’ll consider some factors that can cause labor to take longer than it would on average. Finally, we’ll finish up with your take-away: some suggestions to help keep your labor on track and ensure that should you require medical intervention for progress delay, you really needed it.
How Did We Get in This Fix?
In determining normal labor duration, we’ll focus on first-time mothers because they are much less likely to tick right along than women who have given birth vaginally before. The labor progress standard, the famous Friedman labor curve, came from some studies conducted by Emmanuel Friedman in the 1950s.22 Unfortunately, Friedman developed the curve from a limited number of women, many of whom were managed in ways that would shorten labor length. Half his population had instrumental deliveries, some had cesareans, some had oxytocin to stimulate stronger contractions, and all who had vaginal births had episiotomies.22 Nonetheless, for many decades, the Friedman curve was the basis for the labor graphs hospital staff used to plot labor progress and determine when to intervene for labors that fall off the curve.
Based on Friedman’s data, conventional wisdom became that on average, it took first-time mothers between 8 and 9 hours from onset of labor to reach 4 cm of cervical dilation (latent first-stage labor),6 and that taking more than 20 hours was abnormally long.2 According to Friedman’s data, at about 3 to 4 cm dilation, the pace accelerated, and it took roughly 3 hours to go from 4 cm to full dilation at 10 cm (active labor), or an average rate of 2 cm per hour.14 Once full dilation was achieved, it took another hour on average to push out the baby (second-stage labor).22
The demarcation lines for abnormally slow progress were set at the upper 5% for labor duration. In Friedman’s data, these fell at less than 1 cm dilation per hour from 4 cm onward and taking more than 2 hours from full dilation to the birth.14, 22 Women who progressed more slowly were to be treated with IV oxytocin (Pitocin or Syntocinon) to stimulate stronger contractions, and if this failed to put labor back on track, to be delivered by cesarean or instrumental vaginal delivery.
Better designed studies began appearing in the 1990s that contradicted Friedman’s standards. These studies plotted data from labors in healthy first-time mothers ending in vaginal birth to a healthy baby, although here too, in many of these studies participants could have membranes ruptured, oxytocin to augment labor, and episiotomies, and unlike Friedman, they could also have epidurals. (Epidural analgesia was not yet available at the time he conducted his studies.) These studies painted a different picture.
In first-stage labor, the later studies found an average active-labor duration (4-10 cm) of 6 hours compared with Friedman’s finding of 3 hours.13, 14 The upper 5% for duration in the later studies fell at over 13 hours compared with 6 hours in Friedman. The later studies reported an average dilation rate of 1 cm per hour compared with 2 cm per hour in Friedman, and the demarcation line for the slowest 5% fell at around half a cm per hour compared with twice that rate in Friedman. In other words, Friedman’s “abnormally slow” active labor duration and rate of progress were the average rates in the newer studies. In studies where women had neither epidurals nor oxytocin—in other words, physiologic labors—the upper 5% for active labor duration ranged from 7 hours to over 19 hours, depending on the study, again, very different from Friedman’s findings.1
In the pushing phase, a review of 23 studies found that average durations in first-time mothers were, indeed, around Friedman’s 1-hour mark, but the upper 5% for duration ranged from a bit less than 1 hour to 3 1/2 hours, the latter being the only study in which all participants had an epidural.1 And in studies where women had neither epidurals nor oxytocin, the upper 5% fell at around 2 1/2 hours, not 2 hours.
Important to remember is that all labors in these newer studies ended in vaginal birth to a healthy baby. The upper 5% for first- and second-stage duration represent the upper range of normal, not the threshold at which action should definitely be taken to try to speed up or terminate labor.
In addition, the newer studies also found that the inflection point at which labor kicks into higher gear occurs on average at 5 to 6 cm dilation, not 3 to 4.21
What are the implications of these differences for laboring first-time mothers? For one thing, when they are held to the old standards, they are expected to begin progressing at the more rapid pace of “active” labor when they haven’t actually reached that threshold. For another, they are being diagnosed with progress delay and subjected to the potential consequences of that diagnosis—oxytocin augmentation and instrumental or cesarean delivery—when, in fact, their progress rate is within normal bounds.
What Has Resulted from the New Findings?
The American College of Obstetricians & Gynecologists (ACOG) has embraced some aspects of the new findings.2 In “Safe prevention of the primary cesarean,” it recommends that “6 cm should be considered the threshold for the active phase of most women in labor” and that before this point, “standards of active phase progress should not be applied.” The document’s text acknowledges that women can dilate at half the rate the Friedman curve deems abnormally slow without adverse consequences to their babies, and ACOG’s recommendation states: “Slow but progressive labor in the first stage should not be an indication for cesarean delivery.” It leaves untouched the 20-hour Friedman threshold for diagnosing prolonged early labor on the grounds that no data support changing it—although no data support keeping it either. In second-stage labor, it allows first-time mothers to push for at least 3 hours if mother and baby are doing well and notes that “a specific absolute maximum length of time spent in the second stage of labor beyond which all women should undergo [instrumental or cesarean] delivery has not been identified.”
ACOG may have adopted new standards, but its members have not necessarily followed suit. Many women continue to be managed under the outdated guidelines, and eminent physicians continue to defend them.4, 12 As to why this might be, I can only say that once a practice becomes entrenched—and the Friedman curve has certainly been that—it’s hard to dislodge it.
What Factors Can Increase Labor Duration?
Factors that increase labor duration fall into two categories: ones intrinsic to you or your labor and ones that result from common labor management practices. I’m mentioning them here because in the case of intrinsic factors, knowing whether one of them applies to you will let you know when you might need more time, and knowing what aspects of typical labor management can impede progress will tip you to some you may wish to avoid unless your specific case warrants them.
In first labors, factors intrinsic to the laboring woman or the labor include high BMI;19 bigger baby;5 and malpositioned baby,2 meaning that either the baby is head down but is facing the mother’s belly instead of her back (occiput posterior), the baby is turned toward her side (occiput transverse), or the baby’s head is tilted to one side (asynclitic).
Labor management practices that can impede progress or lead to diagnosis of progress delay include induction of labor,9, 15, 16 especially when cervical ripening is needed;20 hospital admission in early labor;3, 10 confinement to bed;7, 11 epidural analgesia;17 and pushing semi-reclining or flat on the back.8
As far as labor management goes, ACOG recommends giving more time in second stage with an epidural or when there is a malposition: “Longer durations may be appropriate on an individual basis (e.g. with use of epidural analgesia or with fetal malposition) as long as progress is being documented.”2 ACOG also recommends giving more time when inducing labor: “If the maternal and fetal status allow, cesarean deliveries for failed induction of labor in the latent phase can be avoided by allowing longer durations of the latent phase (up to 24 hours or longer) and requiring that oxytocin be administered for at least 12-18 hours after membrane rupture before deeming the induction a failure.” I am not aware of any obstetric guidelines that recommend modifying expectations for any of the other factors I listed above.
The Take-Away
“Time is usually an ally, not an enemy. With time, many problems in labor progress are resolved. In the absence of clear medical or psychological contraindications, patience, reassurance and low or no risk interventions may constitute the most appropriate course of management.”
Simkin 2017, p. 318
The Labor Progress Handbook
Given what I’ve written above, here’s what you can do to stack the deck in your favor:
- Hire a doula. A doula will have strategies to help you progress and to resolve problems with progress if they arise.
- Unless there are reasons you need to be admitted to the hospital early in labor, be prepared to spend this part of your labor at home. Childbirth preparation classes can help you with this, and a doula can also help you be comfortable at home.
- Decline induction of labor for other than medical indications. Possible exception: if the cervix is ready for labor (Bishop score of 6 or more), failed induction of labor is less of a concern.
- Find a care provider whose practices and policies facilitate labor progress and who has an individualized approach to diagnosing and treating progress delay. Here are some questions to help you determine that:
- What is your opinion of doulas? (A positive opinion of doulas is a good sign.)
- What are your policies regarding IVs and fetal monitoring? (These limit mobility, and staying mobile can help you progress.)
- What is your opinion of my pushing in a position other than reclining on my back? (Even with an epidural, you may be able to squat or push on all fours, although you will probably need a spotter, and you can definitely push side-lying, although you or someone else will need to hold up your uppermost leg.)
- What do you consider progress delay? Are there circumstances in which you think women may need more time than usual?
- What’s your approach to resolving progress delay?
- How do you deal with a malpositioned baby?
- Choose a place of birth in which the environment and staff facilitate labor progress. Here are some questions to help you determine that:
- What does the hospital provide to promote mobility and help me with positioning?
- If I prefer to avoid an epidural, what non-drug alternatives do you offer?
- What is the nursing staff’s opinion of doulas?
- What are the typical management policies regarding fetal monitoring, IVs, and pushing position?
- What percentage of women labor with an epidural? (If the number is high, labor care may be built around the premise that all women will be in bed with an epidural, and nurses may not be prepared to work with women who are unmedicated and mobile.)
- Have patience if labor is going slowly. As I quoted above, unless there is concern about the baby’s condition, time is your ally, not your enemy.
- Unless there is a reason not to, request that your caregivers abide by ACOG’s recommendations for preventing cesareans for progress delay.
- Decline a cesarean or instrumental vaginal delivery based solely on exceeding a preset time limit for making progress.
References
1. Abalos E, Oladapo OT, Chamillard M, et al. Duration of spontaneous labour in ‘low-risk’ women with ‘normal’ perinatal outcomes: A systematic review. Eur J Obstet Gynecol Reprod Biol 2018;223:123-32.
2. American College of Obstetricians & Gynecologists, Society for Maternal-Fetal Medicine, Caughey AB, et al. Safe prevention of the primary cesarean delivery. Am J Obstet Gynecol 2014;210(3):179-93.
3. Bailit JL, Dierker L, Blanchard MH, et al. Outcomes of women presenting in active versus latent phase of spontaneous labor. Obstet Gynecol 2005;105(1):77-9.
4. Bernitz S, Oian P, Rolland R, et al. Oxytocin and dystocia as risk factors for adverse birth outcomes: a cohort of low-risk nulliparous women. Midwifery 2014;30(3):364-70.
5. Blankenship SA, Woolfolk CL, Raghuraman N, et al. First stage of labor progression in women with large-for-gestational age infants. Am J Obstet Gynecol 2019;221(6):640 e1- e11.
6. Friedman’s curve and failure to progress: a leading cause of unplanned cesareans. 2017. (Accessed Jun 29, 2022, at https://evidencebasedbirth.com/friedmans-curve-and-failure-to-progress-a-leading-cause-of-unplanned-c-sections/#:~:text=Until%20recently%2C%20most%20women%20in,and%20experienced%20mothers%20eight%20hours%20.)
7. Gizzo S, Di Gangi S, Noventa M, et al. Women’s choice of positions during labour: return to the past or a modern way to give birth? A cohort study in Italy. Biomed Res Int 2014;2014:638093.
8. Gupta JK, Sood A, Hofmeyr GJ, et al. Position in the second stage of labour for women without epidural anaesthesia. Cochrane Database Syst Rev 2017;5:CD002006.
9. Harper LM, Caughey AB, Odibo AO, et al. Normal progress of induced labor. Obstet Gynecol 2012;119(6):1113-8.
10. Kjaergaard H, Olsen J, Ottesen B, et al. Obstetric risk indicators for labour dystocia in nulliparous women: a multi-centre cohort study. BMC Pregnancy Childbirth 2008;8:45.
11. Lawrence A, Lewis L, Hofmeyr GJ, et al. Maternal positions and mobility during first stage labour. Cochrane Database Syst Rev 2013;10:CD003934.
12. Leveno KJ, Nelson DB, McIntire DD. Second-stage labor: how long is too long? Am J Obstet Gynecol 2016;214(4):484-9.
13. Neal JL, Lowe NK, Ahijevych KL, et al. “Active labor” duration and dilation rates among low-risk, nulliparous women with spontaneous labor onset: a systematic review. J Midwifery Womens Health 2010;55(4):308-18.
14. Neal JL, Lowe NK, Patrick TE, et al. What is the slowest-yet-normal cervical dilation rate among nulliparous women with spontaneous labor onset? J Obstet Gynecol Neonatal Nurs 2010;39(4):361-9.
15. Ostborg TB, Romundstad PR, Eggebo TM. Duration of the active phase of labor in spontaneous and induced labors. Acta Obstet Gynecol Scand 2017;96(1):120-7.
16. Rinehart BK, Terrone DA, Hudson C, et al. Lack of utility of standard labor curves in the prediction of progression during labor induction. Am J Obstet Gynecol 2000;182(6):1520-6.
17. Shmueli A, Salman L, Orbach-Zinger S, et al. The impact of epidural analgesia on the duration of the second stage of labor. Birth 2018;45(4):377-84.
18. Simkin P, Hanson L, Ancheta R. The Labor Progress Handbook. Hoboken, NJ: Wiley-Blackwell; 2017.
19. Vahratian A, Zhang J, Troendle JF, et al. Maternal prepregnancy overweight and obesity and the pattern of labor progression in term nulliparous women. Obstet Gynecol 2004;104(5 Pt 1):943-51.
20. Vahratian A, Zhang J, Troendle JF, et al. Labor progression and risk of cesarean delivery in electively induced nulliparas. Obstet Gynecol 2005;105(4):698-704.
21. Zhang J, Landy HJ, Branch DW, et al. Contemporary patterns of spontaneous labor with normal neonatal outcomes. Obstet Gynecol 2010;116(6):1281-7.
22. Zhang J, Troendle JF, Yancey MK. Reassessing the labor curve in nulliparous women. Am J Obstet Gynecol 2002;187(4):824-8.
