Giving Birth Takes Twice As Long It As It Did 50 Years Ago

Giving birth today takes twice as long as it did 50 years ago, and this can affect your chances of a c-section.

My first labor was long. Really long. It lasted from Friday night to Sunday evening. Pain I had anticipated, prepared for, given myself multiple pep talks for, but the duration… It undid me.

As I recently watched a good friend go through a similar labor, some old nagging questions resurfaced: How uncommon is it for women to labor for days? What is a “normal” length of labor, if such a thing exists?

Oddly enough, the medical answers to these questions have just changed dramatically. This is because of a recently completed landmark study of nearly 100,000 labors. The study, which used medical record data collected between 2002 and 2008 from hospitalsm across the U.S., showed unequivocally that we labor much more slowly than we used to. Much, much more slowly.

In fact, our labors have slowed down so much that in 2014 the American College of Obstetricians and Gynecologists (ACOG) revised its definitions of normal and overly slow laborUntil then, the definitions were based on data from the 1950s and 1960s. These data were used to define a “normal” labor duration, how long it takes most women in active labor to reach a full 10 cm of dilation and then to push the baby out. By the same token, these data were used to defined abnormal labor: labors that lasted longer than 19 out of 20 of these labors (the 95th percentile for duration) were considered overly slow or stalled.

The easiest way to see how much our labors have slowed down is look at how long it takes for women in labor to completely dilate. Below are the averages in 1959-1966 and in 2002-2008.

Note that these are the averages among women who delivered a single baby (no twins or higher order multiples) and who delivered vaginally (not by c-sections). First births tend to take longer, so separate plots are given for first-time, second-time, and third-or-more-time mothers.

For first-time mothers:

Screen Shot 2014-11-19 at 12.54.40 PM
Adapted from Laughon et al., 2012, Am J Obstet Gynecol

For second-time mothers:

Screen Shot 2014-11-19 at 1.12.42 PM
Adapted from Laughon et al., 2012, Am J Obstet Gynecol

For third-or-more-time mothers:

Screen Shot 2014-11-19 at 1.21.26 PM
Adapted from Laughon et al., 2012, Am J Obstet Gynecol

Compared to our own labors, our grandmothers’ are downright zippy, reaching full dilation an average of about 2 hours earlier.

The average curves in 2002-2008 are not just slower, they also show a later acceleration. Our grandmothers’ cervical dilation accelerated around 4 cm. Cervical dilation typically begins slowly and then picks up as labor progresses. This was true back then and remains still true today. But the point at which our labors tend to speed up is now around 6 cm. This change is so pronounced and consistent that it led ACOG to revise its definition of when active labor starts. Active labor is now defined as starting when a woman reaches 6 cm instead of 4 cm.

This revision is a big deal. It flies in the face of what most of us have been taught in our birth classes and contradicts much of the information available online. It also changes when the medical clock for active labor starts. Until 6 cm, assuming your water has not broken, there is no expected duration, nor any duration that is considered too long.

So how long does the newly defined active labor phase typically last? In the 2002-2008 cohort:

Screen Shot 2014-12-01 at 1.16.03 PM
Data from the Consortium on Safe Labor, study conducted 2002-2008

Given these dramatic changes, it is no surprise ACOG felt compelled to update its guidelines. ACOG’s new and old definitions are shown below. An abnormally long labor was again defined as above the 95th percentile for duration.

Screen Shot 2014-12-01 at 12.58.50 PM
ACOG’s Definition of Prolonged Active Labor

The Length of Early Labor

According to ACOG’s new guidelines, if you are experiencing regular contractions but are not yet 6 cm dilated, you are in still in what is known as “latent” or early labor.

This early labor period was what made my first labor so long. I took nearly 36 hours to reach just 3 cm. I still remember  how completely demoralized I felt when the nurse told me, on Sunday morning, having been in labor since Friday night.

But was my experience truly atypical? How long does this early phase of labor typically last?

Unfortunately, unlike active labor, what we know about early labor is still mired in the past.

The early phase has traditionally been considered prolonged if it lasts more than 20 hours for first-time mothers, and more than 14 hours for women who have given birth before. These estimates are probably underestimates. They derive from the 1950s and 1960s data and rely upon the old definition of 4 cm for the end of early labor/onset of active labor.

The 2002-2008 study, which was not designed to study early labor, does not provide much help here. The study relied solely on hospital records, so everything that happened prior to admission to the hospital, the time when most of early labor takes place, is a blank.

What the 2002-2008 study does have is information about labor times from 3-4 cm on. Here’s what they found for first-time mothers.  Screen Shot 2014-11-21 at 12.26.43 PM

Let’s make the somewhat crude assumption that labors that start out fast continue to be fast, and those that start slow continue to be slow. Then the median time to go from 3 to 10 cm would be about 6 hours, and the 95th percentile would be about 25 hours.

This table also makes it clear to me that while my early labor the first time probably was unusually long, the rest of my labor, which lasted about 8 hours, was not.


So congratulations, you’re now fully dilated! All that remains is to push the baby out. Easy peasy, right?

ACOG currently recommends allowing at least 3 hours of pushing for first-time mothers and 2 hours of pushing in women who have previously given birth.

The median time for pushing is considerably less than this though.

Screen Shot 2014-12-01 at 3.30.15 PM

The medians are very low compared to ACOG’s limits, because because the distribution of pushing times is highly skewed to the right: Most women push their babies out fairly quickly, in an hour or less, but a significant fraction of women take much, much longer.

Why do our labors take longer than our grandmothers’?

There is no one single all-encompassing explanation. But there are several known contributing factors:

  • We are heavier. The average BMI at delivery in the 1950s and 1960s was around 26. Nowadays the average BMI at delivery is 29-30.
  • We get epidurals. Epidurals slow down labor, especially the pushing phase. Despite this, research does not generally find that epidurals increase the rate of c-sections. So if you need pain relief, fear of a c-section is not a reason to refuse an epidural.
  • We give birth later. The average age of women delivering in the 1950s and 1960s was 24; in the 2002-2008, it was 27.
  • Our babies are larger. Babies in 2002-2008 weighed an average of 100 grams (~1/5 of a pound) more than those born in 1950s and 1960s.
  • More frequent use of pitocin. We are much more likely to have our labors sped up with pitocin than our grandmothers: 31% of women in 2002-2008 cohort received pitocin, versus 12% in 1959-1966. Wait, wouldn’t this make our labors shorter? Yes. Pitocin is so common that it almost surely shortens the average length of labors. So our labors may have slowed down even more than the raw data suggest.

The above reasons do not fully explain why our labors are so much slower. Even when limiting comparisons of 1959-1966 and 2002-2008 deliveries to low-risk women of similar ages, BMIs, ethnicity, and labor characteristics, researchers found that:

“labor in the CSL [2002-2008] cohort was still longer. It would seem therefore that other changes in obstetric practices were likely influential.”  Laughon et al. 2012

What does “other changes in obstetric practices” really mean? Essentially, this is a more sophisticated way of saying, “We don’t have a clue.”

The Bottom Line

In general, we labor much more slowly than we used to. While weight, age, and increase epidurals explain some of this slowdown, the reasons are not completely understood.

In addition, the average labor times are not the best guide for determining how long your own labor is likely to last. There is a huge range of times for each stage of labor. This, incidentally, is why I think birth plans should look more like flow charts. Women should be given a template that asks questions like: How would you like to handle a labor that lasts for 8 hours? And how would you like to handle one that lasts for over 30?

Finally, figuring out how long a labor normally lasts is not an idle personal question. In the U.S., a labor that lasts too long or stalls is the most frequent cause of c-sections among first-time mothers. It is the reason cited for 35% of first-time c-sections.

If you are hoping to avoid a c-section, it makes sense to read ACOG’s new recommendations in full. The new guidelines are significantly more lenient than the old ones and allow much more time for labor to progress on its own.

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Author: Amy Kiefer

I am a research scientist and mother of three munchkins. I live in the Bay Area and when I am not child wrangling and catching up on lost sleep, I love digging into the research on all things fertility, pregnancy, and breastfeeding related.

10 thoughts on “Giving Birth Takes Twice As Long It As It Did 50 Years Ago”

  1. I had an induced labor at 40w5d because of concerns about my gestational diabetes. I went in at almost 3cm, and we used a Foley Bulb to get me to 5cm and early labor/contractions, all in the first 3 hours. I spent the next 45 hours laboring (15 naturally, 30 with pitocin), getting to 6 cm and never getting further. After 48 hours of labor total and still at 6 cm, we all agreed it was time for a c-section. I knew this was a “weird” delivery, although I also know there is no such thing as a “standard” delivery, but reading the stats here put into perspective just how anomalous my experience was. Despite my frustration with the induction process and policies around gestational diabetes, what everyone says is true – none of it matters when that healthy baby is put in your arms.


    1. Thanks for sharing, Jessica. I winced hearing that you were stuck at 6 cm. Ouch. The odd thing is that you are not the only person I know who has gone through a labor like that. I have another friend who was stuck at 8-9 cm, another who got stuck when fully dilated but the baby was at +1, and an acquaintance who got stuck at 8. Two of them ended up having c-sections; the third had a cervical tear and lost a liter of blood within 5 minutes, luckily this happened after her transfer from the birth center to the hospital. And this brings me to an important point. The data from the post probably underestimate the frequency of such occurrences, because the labor curves only include vaginal births. Since a slow or stalled labor is the number one cause of a c-section, excluding all c-section births probably makes our labors look faster than they are. I do wonder how uncommon this kind of experience can be, if I personally know four people who have gone through it. But perhaps my friends and acquaintances are atypical?

      A few people have mentioned that inductions could be slowing labor down. I have not had time to investigate this yet. More soon. And congratulations on your beautiful and healthy little one:-)


      1. Good point, that is a very important distinction if the labor stats don’t include c-section births. Yes, stalled labor is no fun. Hoping for better luck if/when I try again…


  2. I think induction has a lot to do with it… Women are induced BEFORE their due date (I was, twice!) on doctors recommendations for various reasons. Big baby, mom’s discomfort, etc. Also, when women come to the hospital dilated 2-3cm with regular contractions, I think they are being given pitocin and forced into active labor, which then is very slow or stalls because it wasn’t actually time yet. JMO


  3. This is a fascinating post! I was a bit over 40 weeks when I had a membrane sweep, I was stuck at 3-4 cm for about 30 hours, although my contractions were following a pattern of getting closer and closer together despite the lack of dilation, so the last 6 hours or so I was having them every 1-3 minutes and then just constantly, at which point I got an epidural because I don’t know how I would’ve survived otherwise? Then my water was broken by the doctor and I started progressing pretty quickly. Maybe another 8 or 9 hours to go from 4 to 10 cm, and the pushing lasted about 45 minutes. I lost ~1.7L of blood immediately after (long labor, large baby), but they were able to stop the hemorrhaging with pitocin and putting a lot of pressure on my uterus (which apparently hurts, as the doctor kept apologizing, but they extended my epidural so I didn’t feel a thing/was partially unconscious) before having to resort to a hysterectomy.


    1. Being stuck at 3-4 cm for 30 hours is awful! I shudder to think what those labors were like before epidurals. It is unimaginable.
      Incidentally, I also had a long labor after a membrane sweep. I wonder if that is a thing?


      1. I read a fairly comprehensive review of methods for inducing labor, and there was this: “Our search identified one Cochrane systematic review of 22 trials which included 2797 subjects that compared membrane sweeping with oxytocin, PGE2, or no treatment [33]. There was no difference in rates of caesarean deliveries, serious neonatal morbidity, perinatal death, serious maternal or neonatal infections when comparing membrane sweeping with no treatment.” ( Before having it done, I read a lot about them, and they’re generally regarded as safe with benefits outweighing any risks. But… I just don’t know. After that experience, I certainly wouldn’t do it again, and I have a hard time recommending it to others (only if their doctors are wanting to induce because they’re past their due date?).


      2. Interesting! The lack of increase in c-sections would imply (indirectly) that membrane sweeps do not lengthen active labor, at least, since an overly long labor it the leading cause of c-sections in the US.


  4. I had a 46 hour labor with my 1st and just 6 hours with my 2nd (9 minutes pushing). With my 1st I delivered at a hospital. I first labored at home for 18 hours. My labor slowed and stalled out at the hospital stuck at 3-4 cm. At 36 hours I finally had an epidural and took a nap while my tired body dilated to a 10. Pushing took an hour. With my second I opted for a home birth. I woke up with mild contractions around 5am. When I deliver my baby at 11:36 am after just 3 pushes I declared “its only lunchtime? I could eat a sandwich!” I have no idea if this is true but I genuinely feel my anxiety level was much lower being in the comfort of my own home, and supposedly animals can delay labor if they’re in dangerous situations until they find a secure nook in which to birth…I don’t like hospitals. Maybe they used to be more pleasant? My mom always said she had steak and lobster after she delivered us and spent 3 days there to recover…sounds more pleasant to me…so many unknown qualitative factors to consider…


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