Science & Sensibility

Iatrogenic (adjective): induced in a patient by a health care provider’s activity, manner, or therapy. An iatrogenic disorder is caused by medical personnel or procedures or develops through exposure to a health care facility.

Iatrogenic norm: a defined range of normal values for a biological process that, rather than describing actual normal physiology, instead measures the consequences of a health care provider’s beliefs, actions, or therapies or the effects of exposure to a health care facility.

Clinicians today base labor management on norms for cervical dilation rate in active phase labor (assumed to begin somewhere between 3 and 5 cm dilation in women contracting regularly) derived from research conducted decades ago by Friedman and colleagues (the famous “Friedman curve”). According to this research, in first-time mothers, the slowest 10%, an arbitrary cutoff for abnormally slow progress, dilate at a rate of 1.2 cm per hour or less. This norm has been enshrined in the “action lines” of the graphs of “dilation versus time” routinely used to manage labor. The “action” taken when women fail to progress at this minimal rate is administration of intravenous oxytocin to strengthen contractions, and such women are at high risk for cesarean surgery for labor dystocia. If this criterion is overly stringent, women with normally progressing labors will be subject to potentially harmful treatment and surgical delivery unnecessarily.

Concern over this possibility led a group of investigators to conduct a systematic review of studies analyzing active labor duration, progress rate, or both in active first-stage labor in first-time mothers, and the lead author, Jeremy Neal, presented the results at the recent Normal Labour & Birth International Research Conference. Neal began his talk with a look at the body of evidence that gave rise to this concern. I won’t bore you with the details, but suffice it to say that studies using Friedman’s norms for progress diagnose anywhere from one-quarter to one-half or more of first-time moms as requiring treatment for abnormally slow progress. If progress is abnormal in that many women, then something is wrong with the definition of normal, or, as Neal put it:

Either many nulliparous women are admitted prior to progressive (active) labor yet held to dilation expectations of “active‟ labor and/or common expectations of active labor dilation rates (e.g. 1 cm/hr) are unrealistically fast.

The group’s review pooled data from 25 studies encompassing thousands of low-risk first-time mothers with spontaneous labor onset at 36 weeks of pregnancy or more. It found that contrary to Friedman, 1.2 cm was actually the mean rate of dilation, not the rate in the slowest 10%, and the limit for the threshold of slowest acceptable progress rate fell at 0.6 cm, half that rate. (This, by the way, is not a physiologic norm because studies included women with epidurals and labor augmentation, and since all data came from hospital studies, laboring women would have been subject to policies that could affect progress rate such as confinement to bed. That being said, the review found that epidural use did not change results.)

Neal then added that active labor is assumed to progress at a constant rate, but some data suggest that rate of progress may be slower at the beginning of active phase and accelerate as it continues. In other words, the action “line” is another iatrogenic norm because it should be an action “curve.” If this is true, using an action line would put even more women progressing normally in early active phase in jeopardy of the “dystocia” diagnosis and all that follows.

Neal concluded with: “Revision of existing ‘active’ labor expectations and/or revision of criteria used to prospectively identify active labor onset is warranted and such efforts should supersede efforts to ‘change’ labor to fit existing expectations.” “From his mouth to God’s ears,” as they say—or at least to the ears of obstetricians.

Nevertheless, while revising norms to match reality would take a big step in the right direction, I would argue it doesn’t go nearly far enough because it still sticks us with the assumption that active first-stage dilation progresses smoothly. Anyone who has spent time with laboring women knows that this is often not the case. Neat graphical lines (or curves) come from averaging many highly variable individual labors, so the very expectation of how labors progress, at whatever pace, is itself an iatrogenic norm.

Moreover, the published review points out that both the old and the proposed new threshold for “abnormal” are statistically derived (e.g. two standard deviations beyond the mean). No study links a cut point for “abnormally slow” with an increase in perinatal morbidity, but averting adverse outcomes should form the basis for intervening medically because of the risks of intervention. In fact, even if a study tried to establish an outcome-based threshold, it would be hard to determine whether the increase was due to labor duration per se or to the interventions used to treat slow labor. So we have yet another iatrogenic norm, this one having to do with a definition of “abnormal” with no clinical significance.

In short, forcing labor to conform to artificial, arbitrary guidelines does more harm than good. A simplistic cookbook approach to the knotty problem of labor dystocia has obvious appeal, but what is truly needed to achieve the best outcomes with the least use of medical intervention is thoughtful evaluation, individualized care, and above all, patience so long as mother and fetus are tolerating labor. Labor graphs and action lines do no more than exemplify H. L. Mencken’s truism, “For every complex problem there is a solution that is simple, neat—and wrong.”

Henci Goer Uncategorized labor progress, Normal Labour & Birth Conference, Systematic Review

The (in)famous Wax home birth meta-analysis hit the scene over a month ago. But the buzz doesn’t seem to be dying down. In the weeks since the original pre-publication and press release, editors at The Lancet and BMJ have both weighed in, and there’s a steady stream of media attention. While all of the media have dutifully quoted midwives in leadership positions saying the meta-analysis is flawed (an assessment with which I agree), I still keep coming back to the question I asked in my earlier post – did we need a meta-analysis to establish the neonatal outcomes of planned home birth? We had, after all, a very large, methodologically rigorous study on home birth safety involving over a half million women that was published less than 2 years ago. Won’t that suffice?

I had a chance to interview two of the researchers who conducted that study when I was in Vancouver for the Normal Labour & Birth International Research Conference. Simone Buitendijk, MD, is Professor of Maternal and Child Health and Midwifery Studies at the Academic Medical Center of Amsterstam and heads up the Child Health Programme at the Netherlands Organisation for Applied Scientific Research. Ank de Jonge, the study’s lead author, is a practicing midwife with a PhD in public health who works at the Midwifery Science section within the EMGO Institute for Health and Care Research at VU University Medical Center in Amsterdam. I gained some new insights from them about their research and the Wax meta-analysis. Based on those interviews, and despite having written about the meta-analysis twice already, I thought it was time to ask anew: which is the “better” evidence for determining neonatal outcomes of planned home birth: the de Jonge cohort study or the Wax meta-analysis? Let’s have a look at some objective criteria and see how each study measures up.

Study size (home birth group):

• Wax: 9,811
• de Jonge: 321,307

That’s right, the Dutch neonatal mortality analysis is 33 times the size of the neonatal mortality meta-analysis. And believe it or not, this was BRAND NEW news to me that I didn’t realize until I spoke to de Jonge and Buitendijk. Although I had access to the full-text of the Wax meta-analysis and in fact looked critically at it (heck, I blogged about it!), I completely missed the fact that while the de Jonge study was “included” in the meta-analysis, it was excluded from the analysis of neonatal mortality, which was the major finding given so much attention by the media.  On the one hand, I’m pretty embarrassed to have made such a major error. On the other hand, it just underscores how misleading it can be for professionals or lay people to read headlines about a meta-analysis of “hundreds of thousands” of births finding triple the neonatal death rate.  Wax’s neonatal death data don’t come from hundreds of thousands of births at all. Not by a long shot.

Mechanism to ensure data were from planned home births:

• Wax: mechanism varies across the included studies. In Pang et al., which contributed 63% of the home birth data and accounted for 12 of the 18 neonatal deaths in normally formed newborns, researchers relied on birth certificate data that did not differentiate between planned and unplanned home births, and assumed that any birth certificate for a baby born at home at or beyond 34 weeks, signed by a midwife, nurse, or doctor was a planned home birth, a method that has not been scientifically validated and has been widely criticized. Unplanned home births are riskier than planned home births with qualified attendants.
• de Jonge: midwives routinely record the planned place of birth in a national perinatal database that covers 99% of births and is linked to another database of neonatal deaths by a validated method. Planned place of birth was unknown for 8.5% of the population, and the outcomes of this group were analyzed separately and reported.

Definition of neonatal death:

• Wax: death of a live-born infant between 0 and 28 days
• de Jonge: death of a live-born infant between 0 and 7 days (the World Health Organization definition of early neonatal death)

The appropriate definition of neonatal death has been a major bone of contention in the comments on this and other blogs that criticized the Wax meta-analysis.  Both 0-28 days (neonatal death) and 0-7 days (early neonatal death) are accepted definitions. Proponents of using early neonatal death argue that it is more sensitive to events occurring around the time of birth, such as hypoxic injury resulting from inadequate fetal monitoring or a sudden emergency like a cord prolapse or placental abruption. Indeed, some of the late (8-28 days) neonatal deaths reported in Wax resulted from sudden infant death syndrome, a condition that has nothing to do with planned place of birth. On the other hand, proponents of using 0-28 day mortality point out that some babies experiencing severe hypoxic injury in labor or birth may be kept alive for many days in a modern neonatal intensive care unit.  Their deaths should be counted as birth-related even if they don’t die as soon after birth.

Regardless of which is the more appropriate measure, I was shocked by something de Jonge and Buitendijk revealed in their interview. Wax never contacted them to ask for their 8-28 day mortality data. It is standard practice among researchers who conduct meta-analyses to contact the authors of the original papers to obtain unpublished data, clarify methodologies, or ask for data in a compatible format. One would think that if Wax was truly interested in whether planned home birth caused neonatal death up to 28 days, he would be very motivated to get his hands on the Dutch data set. And while de Jonge and Buitendijk told me that those data are not as complete as the early neonatal death data (because some pediatricians don’t reliably enter their patients’ data), they do in fact have the data up to 28 days and would have supplied it to Wax had he asked. Instead, they have done the analysis themselves and submitted it for peer review.  (Therefore, we’ll have to wait for the results.)

What were the characteristics of the population?

• Wax – no requirements for home birth eligibility were defined for inclusion in the meta-analysis. Individual studies included in the meta-analysis varied in their mechanisms for determining eligibility. As noted above, the largest study that contributed the majority of neonatal deaths relied on birth certificates. Women with any of 18 medical conditions documented on the baby’s birth certificate were excluded. Neither the study authors nor Wax and colleagues comment on whether this is a reliable method for defining “low-risk”. (As someone who routinely completed birth certificates when I was practicing, my guess is that it isn’t.)
• de Jonge – National guidelines (“Obstetric Indication List“) define who is eligible for primary midwifery care and home birth. These conservative guidelines ensure that the population of women having planned home births are healthy and at very low risk of complications.

The Dutch study has been criticized because it is, well, Dutch – midwifery and home birth in the Netherlands are highly regulated and integrated into the system, and there are clear eligibility guidelines. The same isn’t true of the United States, so we can’t generalize the results here or elsewhere where home birth is marginalized (e.g., Australia). What the Dutch study gives us, though, is a clear model to emulate in order to make sure home birth is as safe as it can be – regulate midwifery, provide continuity of care for women who need to be referred, and make sure only low-risk women are having home births. Instead of acknowledging this and moving forward to optimize safety, Wax and colleagues chose to mash together data from five different countries and four different decades with no attention paid to which women were and were not eligible and spit out an authoritative answer to the question, “Is home birth safe?” “Is home birth safe?” is a bogus question to which there is no answer. Context, training, system integration, and perhaps above all else the characteristics of the population matter. Any study worth its salt will describe these factors in as robust detail as is feasible. Combining and meta-analyzing data from dissimilar contexts may make sense in other areas of health care, but when context is everything, what’s there to gain?

A note about comments: please keep it civil and on point. I’m OK with debate, discussion, and disagreement. Name-calling, personal attacks, and other degrading commentary will be deleted or edited.

Amy Romano Uncategorized Home Birth, media, meta-analysis, Normal Labour & Birth Conference, safety

[Editor's note: This is a guest contribution about the concurrent session at the Normal Labour & Birth International Research Conference titled Assessing Interactions Between Culture and Choice. Priscilla Hall (a second year PhD student at Emory University Woodruff School of Nursing), Esther Shoemaker (a first year PhD student in the Population Health program at the University of Ottawa), and Kathrin Stoll (doctoral fellow at the Centre for Rural Health Research) each presented their research. - AMR]

Thank you Amy and readers for allowing me the great opportunity of contributing my conference analysis to Science & Sensibility.

At no other conference has choosing between concurrent sessions been so difficult. However, from the moment the schedule was posted some weeks ago I knew there was one I had to attend. Assessing Interactions Between Culture & Choice focused on today’s generation of mothers and what shapes their perceptions, experience and consequently choices about birth.

Generation Y women are today’s young mothers and will make up the bulk of midwives’ clients in the approaching years. What shapes their perspectives on pregnancy and birth? And how will their expectations impact the way they choose to give birth?

Demographics and Influences

Generation Y is loosely made up of adults born between the mid 1980s and the mid 1990s In the conference session, we reflected on what influences this generation of women:

1. This generation is extremely comfortable with technology, having craved the “toys that make the noise” including Nintendo/Sega/Xbox game consoles, mini laptops and iPods. The toys of this generation often involve one-on-one interactions with a computer rather than a friend.

2. The “Audit Society” (Power 1997) is the norm for this generation. The 1980s saw an explosion of auditing activity in UK and American society. Teachers chart performance and activities of students, employees audited their own activities for their employers and health workers began recording up to the minute activities of their patients and one another.

3. To this generation “the most desirable women aren’t women at all – they’re girls.” The womanly shape, once held in esteem by the Greeks all the way up to pre-Twiggy models is seen as overweight to this generation. Smaller frames, straight figures and other pre-pubescent qualities are idealized by Generation Y women (or at least the media they consume). Not ironically, Gen Y has also been referred to as the Peter Pan Generation.

The first two in this hardly exhaustive list of predictors can help to explain how medicalized birth is quickly being assumed as the norm by today’s women. (And as Dr. Eugene Declercq of Boston University pointed out over lunch, the majority of U.S. women are satisfied with their maternity care.) In fact, as UBC doctoral candidate Esther Shoemaker points out from her mixed methods research of young women and new mothers, “Natural” birth to them does not equal “Normal” to us. Natural birth, to most of the women in her study, is synonymous with vaginal birth. Even if labor was induced, an epidural administered or forceps used, the women who gave birth vaginally experienced their birth as natural. I have witnessed this in my own Generation Y peer group of young mothers.

Further, the majority of those Shoemaker interviewed desired a vaginal birth in their antepartum interview, but also voiced an ambivalence about whether or not they actually would give birth that way when the time came. “If something happens I of course will have a c-section.” Oddly enough, perception of safety was not mentioned but the women said they would default to whatever their individual practitioner suggested.

In some cases reported, the practitioner suggested procedures to the Shoemaker participants that increased the degree of medicalized beyond what they expected for their birth. When this occurred, each of the participants changed their plans for their second birth. They either embraced the medical model completely or rejected the medical model in favor of a physiologic birth. So while they were ambivalent or passive first time mothers, they actively created their birth plans for subsequent children. The finding has important implications for today’s mothers as this was true for all Shoemakers’ participant’s whose birth experience was more medicalized than her birth expectation.

Intriguing findings in the studies:

1. Birth, to this generation, is, as UBC scholar Kathrin Stoll points out, a normal physiological process (71%), inherently risky and filled with “unavoidable complications” which necessitate technological interventions.

2. Of the women Stoll interviewed, 70% worried about how they and/or their partners would perceive their bodies during and after pregnancy.

3. According to Shoemaker, who studied what happened in subsequent births among women whose first births were more medicalized than expected, one of two extremes were common. The women would either fully embrace the medical model (e.g., plan a c-section with all the bells and whistles) or she planned to birth at home with no interventions.

The findings of this session’s speakers are all interesting and important for us as midwives, childbirth educators, and activists. When shaping our message about normal birth it is important to meet women where they are, use their language and respect their experience of the world and their bodies. How will we “market” normal birth as we are privileged to know it to the coming mothers?

About Katie Fulmer:

Like many of you, I have birth on the brain and care deeply about the health and wellbeing of our mommas. I am currently a student midwife with Illysa Foster, author of Professional Ethics in Midwifery Practice. My academic focus was Medical Anthropology as an undergrad at the University of Texas in Austin and I look forward to continuing my study of maternity and child care at the PhD level.

Katherine Fulmer Uncategorized Childbirth Education, culture, Normal Labour & Birth Conference, qualitative

Last week, I attended the Normal Labour & Birth International Research Conference in Vancouver, British Columbia. With over 250 attendees from 23 countries, the conference set out to disseminate research about the nature of and optimal care for physiologic labor and birth, and to garner multidisciplinary perspectives on the implications for clinical practice, perinatal outcomes, education, management, collaboration, and policy.

I went as an agent of data dissemination. My job: to use social media (blogs, Twitter) to help make sure the conference proceedings didn’t just rattle around the four walls of the conference hotel, but got out to those in the field working to improve maternity care wherever we each are.

And I have some research I want to write about – really interesting, important research from every discipline you could imagine. But I left the three-day meeting thinking more about the (broken) link between evidence and practice than about any of the new, emerging evidence. I’ll get to the new research over the coming weeks, but first, a look at two stories that dominated the conference.

#1: Home birth on the defensive?

The plenary session by Dutch physician and epidemiologist, Simone Buitendijk, might have highlighted the unique model of midwife-led primary care geared toward planned home birth for low-risk women – a model that many birth advocates and researchers look to as a beacon of hope and reason. Buitendijk herself was co-author of the definitive study of planned home birth safety, a population-based study of over half a million births that found planned midwife-attended home birth as safe as planned midwife-attended hospital birth. And a Cochrane systematic review that came out around the same time as the Dutch home birth study provided definitive evidence that midwife-led care is superior to physician-led or shared models of care. So the Dutch have gotten it right, right? Time to celebrate and emulate? No, instead of a plenary about Dutch primary maternity care as a model to emulate, Buitendijk’s talk was a sobering call to action.

According to Buitendijk, in spite of this evidence (or perhaps in direct response to this evidence?) a well-coordinated media campaign in the Netherlands over the past year has emphasized the dangers of home birth, pointing to an entirely different body of evidence: comparative data showing that Dutch perinatal mortality rates are higher than those in other European countries. Although only about 30 of the 1700 Dutch perinatal deaths occurred at home, and perinatal mortality at the population level is affected far more by incidence and management of preterm birth and congenital anomalies than by the labor and birth care of low-risk women with term pregnancies, the Dutch mass media have made this a story about midwifery care and home birth. The result: the rate of home birth has dipped below 25% for the first time in Dutch history.

#2 VBAC is Back?

Eugene Declercq, who gives – hands down – the world’s most engaging and fun lectures about perinatal statistics, had the pleasure of making an 11th hour revision to his plenary talk on vaginal birth after cesarean (VBAC) thanks to ACOG, who released their new VBAC practice guidelines at 5pm the day prior. (Hat tip to yours truly for tipping him off about the new guidelines. I even got written into his plenary remarks, as the young woman with whom he had a “stimulating conversation” that led him to “stay up all night.” Har har, Gene!)

Anyway, we see in Declercq’s talk the familiar story of how VBAC rates increased briefly then plummeted in the early 2000′s as a result of new research on uterine rupture and, more precisely, an editorial by the ob-gyn editor for the New England Journal of Medicine saying that planned repeat cesarean is “unequivocally” safer than planned VBAC.

Research driving practice! That is, if the research (or overzealous interpretations of it) supports restricting practice.

Where’s the up-tick in VBAC rates when the Cochrane systematic review was published in 2004 concluding that “Planned elective repeat caesarean section and planned vaginal birth after caesarean section for women with a prior caesarean birth are both associated with benefits and harms?” The up-tick isn’t there because by then research wasn’t driving practice – ACOG guidelines calling for “immediately available” emergency obstetric care in VBAC labors were driving practice. And it wasn’t the NIH Consensus Development Conference on VBAC or the massive AHRQ systematic review underpinning the conference (i.e., evidence) that have been heralded as the beginning of the end of hospital “VBAC bans,” it’s ACOG’s (somewhat noncommittal) move away from the “immediately available” standard.

Evidence is not driving practice. Between evidence and practice there lives some kind of cocktail of power, money, activism, media, influence and serendipity (and preservatives). The relative strength of the ingredients dictates how practices evolve. Keeping with the cocktail metaphor, the VBAC plenary ended with an invitation to consumers and our advocates to shake things up – activism being the best hope for ACOG’s new guidelines to be used to drive meaningful change for the many, many childbearing women in the United States with scarred uteruses.

This all reminds me of a third plenary talk at the Normal Birth Conference – Patti Janssen’s lecture, Transforming Research into Policy: Ingredients of Influence, in which she quotes social scientist, Martin Rein.

It also reminds me of Kay Dickerson of the Cochrane Collaboration who said, “We are only to get evidence-based healthcare in this country through consumer activism.”

More on Janssen’s plenary, and updates on the research, coming soon.

Amy Romano Uncategorized ACOG, Home Birth, maternity care systems, NIH Consensus Conference, Normal Labour & Birth Conference, VBAC

My intention was to have daily round-ups of the Normal Labour & Birth International Research Conference on the blog and follow it with some in-depth pieces over the next few weeks.  But between a packed agenda, phenomenal networking opportunities, a gracious hostess who dragged me (neither kicking nor screaming) to see an international fireworks competition over the harbor last night, and jet-lag, I haven’t been able to blog one bit.  The good news is that I have about 6 months worth of blog posts I could write out of this conference. So stay tuned for some quick-hit pieces and some more depth analysis, coming soon!

In the meantime, 140-character-sized updates from the conference are constantly streaming on Twitter.

"Cascade of Normal" from Vicki Van Wagner's talk on midwifery in an Inuit region of Arctic northern Canada

Amy Romano Uncategorized Normal Labour & Birth Conference