Archives for posts with tag: Friedman’s curve

New recommendations from both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal Fetal Medicine (SMFM) seem revolutionary.  Their new joint consensus statement advises abandoning the time restrictions on labor established by misguided adherence to Friedman’s Curve.  Here are some of the new recommendations, which are designed to lower the primary cesarean rate:

  • Allowing prolonged latent (early) phase labor.
  • Considering cervical dilation of 6 cm (instead of 4 cm) as the start of active phase labor.
  • Allowing more time for labor to progress in the active phase.
  • Allowing women to push for at least two hours if they have delivered before, three hours if it’s their first delivery, and even longer in some situations, for example, with an epidural.
  • Using techniques to assist with vaginal delivery, which is the preferred method when possible. This may include the use of forceps, for example.

Aside from being written as if an epidural is unusual (60%-80% of first time mothers have epidurals), these guidelines have amazing potential to lower the rate of cesareans by justifying longer time for women to labor and reducing obstetricians’ justifications for their “failure to wait.”

The question remains, however, whether these new guidelines really will change practice in any meaningful way.  Even the joint consensus statement from ACOG and SMFM says,

Changing the local culture and attitudes of obstetric care providers regarding the issues involved in cesarean delivery reduction also will be challenging.

They go on to note that systemic change (meaning things like changes in required hospital protocols) is likely to be essential for significant practice change to occur, and they also argue for tort reform (discussed below).

People often say that obstetricians perform cesareans because the reimbursement is higher, and there are studies that indicate that this is true.  Doctors, however, are not always paid more for cesareans, and when they are, the difference is often only a few hundred dollars–not chump change, but probably not the major motivator for those in one of the most highly paid medical specialties.  The increase in birth costs for cesareans is primarily for the hospital resources: the operating room, post-operative care, and a longer hospital stay for the woman and her baby.  Contrary to what some studies have found, according to a conversation I had with Alabama Medicaid officials, when Alabama changed its Medicaid reimbursement a few years ago to be the same for cesareans and vaginal births, officials were disappointed to find it did not reduce the cesarean rate.  Here is a graph based on CDC data from Jill Arnold’s


So what does drive high cesarean rates if it’s not all about the financial greed of physicians looking to make a couple hundred bucks through slice and dice obstetrics?

Some cite malpractice suits as a major motivator.  While malpractice premiums do appear to impact c-section rates, the effect is relatively small.  Rather than actual malpractice suits, according to Theresa Morris’ Cut it Out, it is  fear of them that drives OBs toward cesareans.  According to Childbirth Connection’s comprehensive report, Maternity Care and Libility, ACOG’s 2009 survey of OB practitioners reported that liability fears had led 29% of respondents to increase their use of cesarean and 26% to stop performing VBACs. Here’s another graph from Jill:

lawsuit csec

In his excellent New Yorker article on “how childbirth went industrial,” Atul Gawande points to the predictability and reliability of cesarean over vaginal birth, which makes doctors likely to choose cesarean over less invasive procedures (such as forceps deliveries) that may be risky in the hands of those without enough training, experience, or practice:

Is medicine a craft or an industry? If medicine is a craft, then you focus on teaching obstetricians to acquire a set of artisanal skills….if medicine is an industry, responsible for the safest possible delivery of millions of babies each year, then the focus shifts. You seek reliability. You begin to wonder whether forty-two thousand obstetricians in the U.S. could really master all these techniques….[O]bstetricians decided that they needed a simpler, more predictable way to intervene when a laboring mother ran into trouble. They found it in the Cesarean section….We have reached the point that, when there’s any question of delivery risk, the Cesarean is what clinicians turn to—it’s simply the most reliable option….Clinicians are increasingly reluctant to take a risk, however small, with natural childbirth.

Yet c-sections also pose real risks, as this table from the joint consensus statement indicates:

Table 1. Risk of Adverse Maternal and Neonatal Outcomes by Mode of Delivery
Outcome Risk
Maternal Vaginal Delivery Cesarean Delivery
Overall severe morbidity and mortality*† 8.6% 9.2%*
0.9% 2.7%†
Maternal mortality‡ 3.6:100,000 13.3:100,000
Amniotic fluid embolism§ 3.3–7.7:100,000 15.8:100,000
Third-degree or fourth-degree perineal laceration|| 1.0–3.0% NA (scheduled delivery)
Placental abnormalities¶ Increased with prior cesarean delivery versus vaginal delivery, and risk continues to increase with each subsequent cesarean delivery.
Urinary incontinence# No difference between cesarean delivery and vaginal delivery at 2 years.
Postpartum depression|| No difference between cesarean delivery and vaginal delivery.
Neonatal Vaginal Delivery Cesarean Delivery
Laceration** NA 1.0–2.0%
Respiratory morbidity** < 1.0% 1.0–4.0% (without labor)
Shoulder dystocia 1.0–2.0% 0%
Abbreviations: CI, confidence interval; NA, not available; NICU, neonatal intensive care unit; OR, odds ratio; RR, relative risk.

(Note that cesarean’s near-quadrupling of maternal death risk is not causing a call to ban non-medically essential cesarean).

Another factor in physician preference for cesarean–one that is closely tied with money–is time.  As one prominent obstetrician once told me, the money itself isn’t the issue–what’s a couple hundred dollars to someone whose salary is well into six figures?  It’s time.  A cesarean takes 40 minutes.  A vaginal birth can drag on for hours and hours, and the timing is completely unpredictable.

This report on Maternity Care Payment Reform from the National Governors Association explains that the optimum timing possible with cesarean is personally convenient as well as financially lucrative–but not because of the payment for the cesarean itself:

[P]lanned cesarean deliveries have lower opportunity costs for obstetricians and facilities. For facilities, spontaneous vaginal deliveries may be more difficult to plan and manage compared to scheduled cesarean deliveries. With a planned cesarean delivery, hospitals can schedule operating room time and ideal hours for nursing staff. For providers, scheduling a cesarean birth ensures that they will be the ones to perform the delivery and they will not have to transfer care and associated payment to a colleague or be delayed from office or other hospital duties.11 In addition to securing reimbursement, having scheduled births allows providers more time to schedule billable procedures.

Even in vaginal births, the emphasis many obstetricians put on time is obvious.  Elective inductions allow for births to be scheduled at the physician’s convenience (and while this may sometimes be convenient for the pregnant woman also, you can bet that she does not get to pick a time that would be inconvenient for her doctor).  ACOG guidelines on labor induction and augmentation discuss the reduction in labor time that can occur with Pitocin administration in positive terms (without any indication that this is preferred by laboring women).

In my tours of hospital labor units, it has not been uncommon for every laboring woman on the board to have a Pitocin drip to “help them along.”  A friend of mine–one who was amenable to a highly medicalized birth and had an epidural in place–said her obstetrician walked into the room when she had dilated to 10 centimeters and said, “Okay, you have two hours to push this baby out and then I’m going to have to do a cesarean.”  This did not even meet old time guidelines, which indicated a three hour pushing time for first time mothers who had an epidural.

The website My OB Said What? is full of anecdotes about practitioners who value their own time over the normal progression of  labor.  A few examples:

Some doctors also feel a therapeutic mandate to “do something,” which is often counterproductive in a normal labor.  Obstetrician and ethicist Paul Burcher notes that a “therapeutic imperative” is essentially another term for “the inertia that prevents physicians from abandoning ineffective therapies because no better alternative yet exists.”  Burcher is writing about bed rest, but as with threatened miscarriage, the current “better alternative” in a normal labor is to do nothing at all.  As Dr. Burcher says,

It takes courage to do nothing, but when we have nothing of benefit to offer we must refrain from deluding ourselves and harming our patients.

Here’s hoping that ethics will trump time and money and lead to genuine change in practice.  But given the historic difficulties obstetricians have with implementing evidence based practice and the slow obstetric response to reducing (rather than increasing) intervention, given the average time it takes to put an innovation into routine practice, we may have at least 17 years to wait.


Procrustes took in lodgers on the road to Athens, but they had to fit his proffered bed.  If the prospective lodgers were too short, he stretched them, and if they were too tall, he cut as many inches as necessary from their legs. As a result, according to Encyclopedia Brittanica, “The ‘bed of Procrustes,’ or ‘Procrustean bed,’ has become proverbial for arbitrarily—and perhaps ruthlessly—forcing someone or something to fit into an unnatural scheme or pattern.”


Enter American Obstetrics.

Human beings generally are within  a range of normalcy.  As such, we do not expect everyone to be exactly the same height or weight.  We don’t say that everyone should have exactly the same blood sugar reading, and we accept a range of blood pressure readings as healthy.  A woman could be 5 feet or 6 feet tall–we might think that one woman was short and the other tall, but we probably wouldn’t consider either to be abnormal–certainly not to the point that we would medically intervene to change her.  There is an average, to be sure, but there is a range around that average that is considered “normal.”


But that range, in the mind of an obstetrician, may become very, very small.

A friend of mine, pregnant with twins, had one twin who was substantially smaller than the other.  As the pregnancy came close to 36 weeks gestation, the OB ran some tests to see if the smaller twin was suffering from intrauterine growth restriction.  The numbers came back within the normal range, but the doctor didn’t like them because they were on the low side of normal.  She told my friend that a cesarean was necessary, and as a result, the larger twin, not ready to be born, spent a week in the NICU with respiratory problems.

The length of a normal, healthy pregnancy can vary by as much as 5 weeks, but new definitions recommended by the American College of Obstetricians and Gynecologists (ACOG) have narrowed the definition of  normal gestation to a 2 week window.  Only babies born at 39-41 weeks are “term”:

Recommended Classification of Deliveries From 37 Weeks of Gestation

  • Early term: 37 0/7 weeks through 38 6/7 weeks
  • Full term: 39 0/7 weeks through 40 6/7 weeks
  • Late term: 41 0/7 weeks through 41 6/7 weeks
  • Postterm: 42 0/7 weeks and beyond

As Linda Hunter observes, accurately calculating a due date from the first day of the last menstrual period (LMP)  depends on “the woman’s accurate recall of her LMP; the regularity of her cycles; the presence of early or light bleeding; and other factors, such as oral contraceptive use or breastfeeding that could influence ovulation timing.  There can also be some variation in the actual timing of ovulation, even in the presence of a seemingly normal 28-day menstrual cycle.”  And many women do not have 28 day cycles, though the due date is generally calculated the same way regardless.

Ultrasound screening is generally more accurate at estimating gestational age than using the LMP, but this method also has limits.  Hunter reminds us that screening is only reliably accurate if done in the first trimester.  In addition, she says, “Ultrasound’s accuracy depends greatly on the skill of the person performing the examination and the quality of the images, not to mention the size of the patient and the fetal position.”  She notes that ultrasound dating is useful because many women’s due dates are estimated too early under the LMP method, and thus many women undergo unnecessary inductions for “postdate” pregnancies (late term or post term, according to the new definitions) that are actually still well within the “term” range.

Even within the two week window, many OBs push for induction as soon as a woman reaches 39 weeks.  The average pregnancy length has become shorter and the range of gestational age at birth narrower as induction has more frequently been used to force women’s bodies to conform to obstetrical definitions of term.  In the past decade, the average length of pregnancy has decreased from 40 to 39 weeks, in part because of scheduled inductions and cesareans to make women’s pregnancies fit an increasingly narrow definition of “normal.”

Perhaps the most egregious narrowing of the normal window comes from Friedman’s curve.  Friedman observed the labors of women in the 1950s, and came up with a”normal” trajectory for a labor to progress (click to enlarge):


As Rebecca Dekker at Evidence Based Birth explains, Friedman’s curve is now obsolete.  Women are no longer heavily sedated in labor.  Their size is different, their nutrition is different, their lifestyles are different, and most women labor much longer now than they did during the time of Friedman’s observations.  Here is a graph that shows Friedman’s curve against the typical labors of contemporary women (click to enlarge):

Screen Shot 2013-12-30 at 7.04.03 PM

Despite the historical changes, many OBs cling to Friedman’s curve as the definition of “normal” labor, and give women Pitocin and other drugs to try to make an uncomplicated labor conform to Friedman’s curve.  If the woman’s body still does not conform, she may wind up with a cesarean for “failure to progress,” even though her labor was progressing fine.

A debate has now arisen over diagnosis of gestational diabetes (and I’m sure this debate will continue).  New standards proposed would lead to nearly 20% of pregnant women being diagnosed with gestational diabetes.  Although the NIH issued a consensus statement that the old standards should remain for now, some doctors are now concerned by blood sugar readings that were considered perfectly normal by everyone just a few years ago.  It should be noted that women experience many negative effects with a diagnosis of gestational diabetes, including “constant worry and anxiety over their baby, self-blame and guilt, and more medicalization throughout the prenatal care and delivery,” all of which, like gestational diabetes itself, can lead to negative health consequences.

The narrowing range of obstetric normalcy mirrors other areas in which women are expected to conform to a narrow standard–and literally to cut their bodies to conform:


There are many ways to be a human being and to grow one.  In the words of Dr. Anne Marie Jukic,

[N]atural variability may be greater than we have previously thought, and if that is true, clinicians may want to keep that in mind when trying to decide whether to intervene on a pregnancy.

Women do not need to be cut open because their bodies do not follow a line on a graph.  They do not need to be shamed and blamed for numbers a doctor doesn’t like.  They do not need to be given medications to force their functions to fit a preconceived idea of what is normal.  Perhaps instead someone could observe the woman and her fetus and see if both appeared to be healthy and developing well, and intervene only when an actual problem arose.

Fitting into a Procrustean version of obstetrics that dictates increasingly narrow ranges of normal does not benefit women or babies–and rejecting such a model would allow more women to emerge from pregnancy and birth physically and psychologically intact.

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