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How Long Can Labor Safely Be?

How Long Can Labor Safely Be?

By regular contributor, Henci Goer

A few weeks ago Kathy Morelli wrote an S&S blog post about a study comparing labor patterns in the 1960s with labor patterns today. The contemporary data were collected by the U.S. Consortium on Safe Labor (CSL), a collection of 19 hospitals, 17 of them teaching institutions, whose primary purpose is “to describe contemporary labor progression and to evaluate the timing of Cesarean delivery in women with labor protraction and arrest.” The study compared women with spontaneous labor onset at term who were carrying singleton, head-down babies and found that after adjustment for differences in maternal and pregnancy characteristics, labors take longer today despite substantially increased use of oxytocin augmentation. The authors attributed the increased length to changes in management practices and concluded: “Since labor times are longer today than in the past, the benefit of extensive interventions such as oxytocin and cesarean delivery in modern labor management needs further evaluation”(Laughon, Branch, Beaver and Zhang, p. 14).

The question still on the table is at what point does increased risk of morbidity from continuing a prolonged labor outweigh the risks of cesarean surgery or instrumental vaginal delivery to curtail it? The CSL study doesn’t answer that question, but we have two studies, one in a single institution and the other a multicenter study, that provide means and extremes for duration of physiologic labor. Both studies were conducted in healthy women in spontaneous labor at term with a singleton, head down fetus who were cared for by midwives. No woman had oxytocin augmentation, epidural analgesia, or an instrumental vaginal or cesarean delivery. Let’s compare data on first-time mothers since they are much more likely to experience progress delay.

 

CSL
n = 43,576

Albers 1999
n = 806

Albers 1996
n = 556

4 cm -> 10 cm
CSL: median (95th percentile)*
Albers: mean (95th percentile)
6.5 (24.0) hr 7.7 (17.5) hr 7.7 (19.4) hr
2nd stage
CSL: median (95th percentile)**
Albers: mean (95th percentile)
0.9 (3.1) hr 0.9 (2.4) hr 0.9 (2.5) hr
epidural 60% 0% 0%
oxytocin augmentation 37% 0% 0%
instrumental vaginal delivery 10% 0% 0%
intrapartum cesarean 16% 0% 0%
5-min Apgar < 7 2% 0.8% 1.1%

*data only from women reaching full dilation
** data only from women having spontaneous birth

As you can see, labor averaged even longer in the physiologic groups without doing any harm to the newborns. As you can also see, the midwifery data blow active management concepts, now enshrined in partograms, out of the water. Setting 1 cm per hour as the threshold for abnormally slow progress—which allows 6 hours to go from 4 cm to 10—means augmenting first-time mothers dilating faster than the average rate!

The CSL investigators point out that half the cesareans in the entire CSL cohort were performed for “failure to progress” or “cephalopelvic disproportion” and reference another study of the cohort finding that “a large percentage of women” (p. 12) had cesareans prior to active-phase labor. Indeed they did. Among first-time mothers with spontaneous labor onset who had cesareans for delayed progress, more than a quarter of them (28%) had the surgery at 5 cm dilation or less. Among induced labors, the percentage soared to half (53%).

Despite their concern about over use of oxytocin augmentation and operative delivery, the CSL investigators also note that the extra two hours of average labor duration in first-time mothers (compared with the 1960s cohort) cost Intermountain Healthcare hospitals, which managed 5439 vaginal births in first-time mothers in 2010, an extra $110.40 per labor, amounting to an annual excess cost of $600,466. They continue: “The implications for healthcare systems and payors are obvious and should drive a reconsideration of modern-day labor process management with an eye towards process improvement” (p. 13). One wonders just what that process improvement might be. The “time is money” argument certainly doesn’t augur for recommendations to have patience and avoid intervening—especially not when intervening via cesarean surgery increases revenue as well as saves money.

They don’t come right out and say so, but clearly the CSL investigators know they have documented a gross overuse of cesarean surgery to cut short (pun intended) perfectly normal labors that pose no excess risk to mothers or babies. The Consortium on Safe Labor has, in fact, exposed that labor in their participating hospitals isn’t very . . . well, . . . safe. Women are ending up with major interventions they don’t really need and, no doubt, some of them are experiencing unnecessarily their consequent complications. What is more, economics provides a perverse incentive for keeping it that way.

 

 

Authoritative Knowledge, Cesarean Birth, Systematic Review, Uncategorized , , ,

  1. April 18th, 2012 at 08:01 | #1

    I need to look for this study from AWHONN, but a few years back they did a study that looked at labor times and found that in first time moms labor should not not even be considered “active” until they are 4-5 cm and that the whole 1cm/hour was too fast. In this particular review, they found that .5 cm/hour was more the norm (and that was after already getting to 4-5cm). The idea that women are getting c-sections before they even get that point really needs to be reexamined.

  2. April 18th, 2012 at 09:20 | #2

    I find it most telling that we are in the year 2012 and don’t have the research on normal, healthy labor and birth to be able to answer these questions with any certainty. That may be because too much of the available research is on interventions, medications, and ‘doing things’ to women. Is that because too much research is funded by the very industries that benefit from the use of these interventions? (fetal monitoring, pharmaceuticals, surgical interventions….).
    It will take the will of consumers and employers who foot the bill for overuse of medical interventions in health care (cesareans and hysterectomies have the highest surgical volumes) to reverse this trend.
    Evidence-based care and the needs of patients/families can’t be optimized until we bring consumers & their employers to the table to leverage hospitals/providers to reduce costs/premiums by focusing on prevention and health instead of disease and over treatment of a normal healthy process. Perhaps we need to educate the public about the reverse relationship between healthcare costs and quality; high-quality care reduces consumer/employer healthcare costs. The conundrum is that it also reduces facility and provider profits.

  3. April 18th, 2012 at 13:54 | #3

    Henci,

    You have such a talent at presenting data in a way that the key point jumps off the page. Thank you for sharing this information!

  4. April 18th, 2012 at 15:24 | #4

    @Rachel
    I’m not sure if this is the study you remember, but I’ve blogged on that issue too: http://www.scienceandsensibility.org/?p=1439. Thanks for bringing up that point.

  5. April 18th, 2012 at 17:56 | #5

    Lori Nerbonne :
    The conundrum is that it also reduces facility and provider profits.

    You have hit on a crucial issue often overlooked. We talk about “cost effectiveness” as a major advantage of physiologic care because it reduces use of tests, procedures, and drugs without compromising outcomes, but cost effectiveness opposes revenue generation. So long as that is the case, there is a huge perverse incentive to maintain the status quo.

  6. April 18th, 2012 at 17:57 | #6

    @Lisa Baker
    You’re welcome! My pleasure!

  7. April 18th, 2012 at 18:29 | #7

    Does anyone know the reason labors appear to be longer now? Are we sure they are actually longer, or do they look longer because women come to the hospital sooner? (Did the women in the earlier studies come in before 4 cm and get measured from 4 cm on the dot, or were that at-or-after 4 cm?) I am an historian, and in the course of doing some related research, I noticed that obstetrics textbooks seem to give shorter and shorter time estimates for labor over the course of the 20th century. I have only looked at this casually, and plan to do it more systematically at some point, but it gave me pause. Is it a matter of actual changing biology? Changing expectations based totally outside of real data? Changing patterns/habits of care? And why does it go the other direction in the last couple decades?

  8. avatar
    Dreamy
    April 18th, 2012 at 19:26 | #8

    Lara–

    My guess (and I made this comment on another recent S&S post) is that the greatly increased prevalence of inductions without medical indication has a lot to do with it. If it is true that women who are not ready to deliver won’t deliver (easily) even if induced, and more women are being induced simply because they are 40 weeks (or 39, or 41), then more women are going to see slow, “unproductive” progress. Just a thought as to one possible factor at work.

    Not to mention, although it’s anecdotal– of all the women I have known to get mainstream OB care in the past 5-10 years, perhaps 75% or more of them have had their due dates reset to an earlier date by ultrasound (usually a few days to a week), and none of them reset to a later date. This, despite the fact– as I understand it– that more women ovulate later than cycle day 14 than earlier. What I suspect is that MANY women are being induced because they are “due” (40 weeks) or “late,” when in fact they are (and/or would have been considered to be, in the past) “early” or just barely “due.” What that leaves us with is this…

    -The best available research indicates that the average first time mother has a 41w1d pregnancy.

    -The *average* woman who has not yet gone into spontaneous labor is induced right around 40 weeks (my guess). Maybe a day or two later, on average.

    -However, the average woman has already had her due date adjusted earlier by several days (also my guess), meaning that the average woman is actually being induced before the actual (or at least prior-standard-of-measurement) 40 week mark.

    -So, by my guesstimation, what we’re seeing is MANY women being induced an average of 1.5 weeks before their bodies would typically be ready. And certainly, this would tend to lead to more dysfunctional and longer labors, including cascades of interventions, often leading to c/s or instrumental deliveries and additional complications.

    Just a hunch, though.

  9. April 18th, 2012 at 21:06 | #9

    @Dreamy
    You are quite right that induced labors take longer, but in this case, they were only looking at women with spontaneous onset. The investigators also compared a subset of low-risk women with similar characteristics (white, maternal age 18-30, prepregnancy BMI 18.5 to < 25.0, nulliparous, gestational age 37 to < 42 wks, birth weight 2500 to < 4000 g, no oxytocin, no gestational or pregestational diabetes, no chronic hypertension or preeclampsia) and still got longer labors in the contemporary group compared with the 1960s group. I think epidural analgesia use (5% vs. 60% in the overall nulliparous group) is a likely factor. Even women progressing fast enough not to receive augmentation in the select subgroup probably progressed more slowly than comparable women laboring with no epidural.

  10. April 19th, 2012 at 15:45 | #10

    Dreamy — another interesting pattern I’ve been noticing as I have been reading 19th century marriage/pregnancy advice manuals is that while pregnancy is estimated to last 280 days, it is counted from the finish of menstruation, not the start of the LMP. Which gives about 41 weeks. At some point, I also plan to write about this, tracking the subtle shift in how the longstanding time-of-gestation estimate is actually calculated, which as you point out, has enormous implications.

    Henci — is there any way to separate out the data for the more recent studies, to try to see the effect of epidurals?

    @Dreamy

  11. avatar
    Lauren
    April 19th, 2012 at 19:55 | #11

    Wow, this is ridiculous. Thank you Henci. I know now that my VBAC would have ended in a c-section give these ‘rules’ had I not advocated for myself and found a practitioner that believed in a woman’s ability to give birth to her baby. I was 3 cm dilated at 37 weeks and dilated approximately 1 cm per week for the next 4 weeks. Ha! Talk about not falling into the normal curve of 1 cm per hour!!! I was then 6 cm dilated at 41 weeks and didn’t go into labor with contractions until my membranes released at 41 weeks and 2 days. At that point my unmedicated, all natural birth lasted a total of 2 hours. With only 20 minutes of pushing my 9 lb 10 oz baby boy entered the world.

  12. April 19th, 2012 at 23:03 | #12

    @Lara
    The data were not reported in a way that allowed seeing the effect of epidurals. Now that I think about it, though, epidural use doesn’t explain why the women in the two Albers studies had even longer labors than women in the CSL cohort. None of them had epidurals. I just shot down my own theory. I’m baffled. Anyone else got any ideas?

  13. April 19th, 2012 at 23:25 | #13

    @Lauren
    Your story raises yet another problem with partograms. Partograms assume labor progresses smoothly. But labor curves represent the average of many women. Anyone who spends time around laboring women knows that dilation in individual women can stop then start again, make quantum leaps–you name it. It can even go backwards and then resume. The whole concept of graphing labor progress is kind of bogus. It gives the illusion of providing guidance while actually distracting from what is really needed: thoughtful, individualized evaluation and therapy.

  14. avatar
    Penny
    April 20th, 2012 at 10:26 | #14

    I had my second daughter at home in the water…. SROM occured around 9:30 sunday morning. I gave birth tuesday morning at 10:25am. i was 3-4 when SROM happened – she was my third child and because i had no internal checks and was not in any hurry i firmly beleive that she was born at HER perfect right moment and all of us were blessed to be a part of it. I know had i been in a hospital they would have augmented before sunday got to evening. Thank you for sharing your wise experience.

    i have had augmented labors and even an induced labor but i have never fallen prey to the cascade of intervention that usually accompanies that action. I have an extra lumbar vertebrae right smack dab wher ean epidural needle would go so i CANNOT get one and luckily i have never had any complications as a result of augmentation or induction. no labor for me has topped that 49 hour mark though!

  15. April 20th, 2012 at 12:48 | #15

    Henci — did the women all report to the hospital prior to 4 c.m. in the 1966 study? Or did some of the women possibly show up more dilated? I know that part of the induction problem at many hospitals is caused by women showing up sooner, and hospitals admitting them rather than sending them home. It’s possible that women were not actually there for some of their post-4 c.m. labor in the earlier trials. If they were really there by 4 c.m., here’s a somewhat less plausible idea: perhaps the women in the recent trial showed up significantly before 4 c.m., rather than immediately before, and were laboring in unfavorable conditions prior to 4 c.m., setting them up for less favorable labors. Or perhaps some substantial proportion had false labor. I’m certainly familiar with anecdotal stories of friends going in, having their labor diagnosed as false, and being offered admittance+induction anyway.

  16. avatar
    amber
    April 20th, 2012 at 14:41 | #16

    Still very uneasy about my first laboring experience. My water broke so I ran to the hospital (because that’s what they make you think you should do). Labor did not jumpstart right away so they induced me. And I’m talking the max pitocin allowed with no pain meds (for about 10 hours). It was intense. “Among first-time mothers with spontaneous labor onset who had cesareans for delayed progress, more than a quarter of them (28%) had the surgery at 5 cm dilation or less. Among induced labors, the percentage soared to half (53%).” I was over 6cm dialated when they said “your baby’s heartrate is dropping and you need a c-section”. Who knows it they were being truthful. I think they wanted to get it over with since I had been there 24 hours at that point. Come to find out, a doula told me after the fact that, of course, 10 hours of full on pitocin would lower the heartrate of any baby. These doctors are FORCING nature to happen. I am pregnant and going for a VBAC this time around. I have 6 more months to do research. I even found a practice (of all midwives) 45 minutes away who supports VBAC’s. Does anyone know how long you can go over 40 weeks if planning to VBAC?

  17. April 21st, 2012 at 22:03 | #17

    The investigators don’t give us that kind of detail from the 1960s cohort. They do explain in the methods section that labor curves were generated by “fitting an interval censored regression,” which I take to be a mathematical means of accounting for the fact that dilation measurement is not continuous. Study investigators also note that the reason they started the dilation curve at 5 cm in women with prior births and 4 in women having a first baby was that women with prior births were more likely to present at a more advanced dilation, which also implies that the curve was a projection.

    I think you may be on to something when you point out that women admitted in early labor may be offered induction instead of being sent home. It may be that this gets charted as “augmentation” if the woman is contracting instead of what it really is. There is a real physiologic difference between giving oxytocin to a woman who has made the transition into active labor and one who has not even though she may be having regular contractions and even making some progress, but while women who were induced were excluded, women who were augmented were not.

  18. April 30th, 2012 at 21:17 | #18

    Ah, but what about the “back door inductions?” That is, the women who are having mild contractions, go to their OB, are checked and found to be 3 cms (as I was at my 40 week visit in my first pregnancy–before I’d even felt any contractions…and then as I was again after I’d been having contractions for 12 hours), and are at that point sent to the hospital, and then are “augmented” when they don’t progress fast enough? To me that is an “induction” because the woman was not yet in active labor…but for this study the woman may have been considered part of the percentage that went into “spontaneous labor” but then got Pitocin.

  19. April 30th, 2012 at 21:45 | #19

    Oh, LOL, I see you already discussed this!

  20. May 7th, 2012 at 13:52 | #20

    amber :
    I am pregnant and going for a VBAC this time around. I have 6 more months to do research. I even found a practice (of all midwives) 45 minutes away who supports VBAC’s. Does anyone know how long you can go over 40 weeks if planning to VBAC?

    I have written about this issue on my Forum, “Ask Henci.” Go to http://www.lamaze.org/OnlineCommunity/AskanExpert/tabid/363/aff/14/aft/31870/afv/topic/Default.aspx. Key point: some studies have found an increase in scar rupture rates in women with pregnancies going past 40 weeks, but *this is because they are more likely to be induced*, not because of anything intrinsic to longer gestation. (Induction, BTW, also decreases the likelihood of vaginal birth.)

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