Archives for posts with tag: risk

I once led a community service project for which middle schoolers baked cookies to deliver to a local shelter.  We brought out the ingredients and began giving instructions when one kid asked if they could eat some of the cookie dough.  Another kid immediately said eating cookie dough would give everyone salmonella.  Within seconds, we had two camps of shrieking middle schoolers, one with members who had eaten raw cookie dough all their lives and were just fine, and the other with members that insisted that eating raw cookie dough would lead straight to a week-long date with the toilet followed by certain death.

A Google search on the subject breaks into similar camps, from “Rejoice!  you Probably Won’t Get Salmonella from Eating Raw Cookie Dough” to “Eating Raw Cookie Dough Can Actually Be Deadly.”

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In fact, there is a tiny risk of contracting salmonella from eating anything with raw eggs in it, including cookie dough, but that risk is very small, and the risk of dying from salmonella is even smaller.  There is also a risk of choking on raw cookie dough, or having an unexpected allergic reaction to an ingredient, or eating too much of it and having a stomach rupture.  And there is a risk of getting salmonella from other foods, such as meat or salad greens–in fact, almost any food could be contaminated.

All of this is to say that everyone assesses risks differently, and that people can get very upset when others don’t assess risks the same way they do.

Enter home birth.

In the New York Times’ “Is Home Birth Ever a Safe Choice?” risk assessment is on everyone’s mind.  Two obstetricians who specifically address risk come to two very different conclusions.

In “Emergency Care Can Be Too Urgently Needed for Home Births,” John Jennings, the current president of the American Congress of Obstetricians and Gynecologists (ACOG) writes,

When women decide where to give birth, they should understand the potential risks involved with their options….evidence shows that although the overall risk of serious childbirth complications remains low, there is still a twofold to threefold increased risk of neonatal death associated with home birth.

This line is almost verbatim from ACOG’s 2011 Committee Opinion, “Planned Home Birth,” which says that “it respects the right of a woman to make a medically informed decision about delivery,” but goes on to say that the only risk obstetricians are obligated to share is the neonatal death death risk as determined by the Wax study.  The Wax study, a meta-analysis of a number of other studies, was widely criticized for drawing faulty conclusions from flawed methods (see e.g. herehere, and here).

Like OBs Grunebaum and Chervenak, who I critiqued in my previous post, Jennings, a professor at Texas Tech, suggests that hospitals strive for more home-like settings and partner more with nurse midwives (CNMs).  He also suggests working with patients to create “action plans”–aka birth plans.

Texas Tech OBs attend births at the Medical Center Health System’s Center for Women and Infants.  The hospital reports to the Leapfrog Group, which says that they have made progress on reducing episiotomies (current rate is 12.2%,), but have low adherence to clinical guidelines for high risk deliveries, which would seem to negate the purpose of having a high-risk birth at the hospital.  In their favor, they do appear to have one of the lower primary cesarean rates in the state for uncomplicated births at just over 12% (an uncomplicated or low-risk birth is generally defined as a healthy mother with a single, head-down, vertex fetus).

It’s hard to determine much from the website other than that they have a lot of nice rooms and that they appear not to do skin-to-skin contact at birth (the nurse takes the baby for suctioning).  They have a short video that shows a woman on a gurney with a nurse showing her what look like two English muffins on a headphone cord.  There is a long sequence on the Ronald McDonald Room where a towheaded boy eats cookies, and then a segment on “Family Centered Care,” which shows a nurse holding a baby in the hospital nursery.  Despite Jennings’ apparent promotion of CNMs, no midwives are listed as practicing there, and a search for midwives on the site yields nothing.  There is no information about developing or following an “action plan.”

OBs who say that hospitals should provide home-like setting, employ nurse midwives, and honor birth plans might want to begin at the hospitals where they themselves practice.

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Jennings also says, “As obstetrician-gynecologists, our goal with any delivery is a healthy mother and a healthy baby.” It’s not as if mothers’ and midwives’ goal is mothers and babies who are sick or dead. Jennings definition of “healthy” seems to be “alive.”  Superfluous slicing, dicing, and infections are not even noted.

The problem with assessing risk only in terms of neonatal death is that the risk of neonatal death is very small, while the risk of other birth complications is fairly large.  Jennings’ hospital aside, the national cesarean rate for low risk births is 26.9% (the overall rate is 32.7%).  This varies tremendously by hospital, with some achieving rates below 5% while others have rates that are over 80%.

Aaron Caughey, who is chair of the department of obstetrics and gynecology and the associate dean for Women’s Health Research and Policy at Oregon Health and Science University’s School of Medicine, does not assume that the risks in home birth are automatically unacceptable.  Instead he asks, “In Home Birth, What Risk is Acceptable?

In discussing a recent British report about home birth, Caughey acknowledges  “increased C-sections, episiotomies and epidurals as a reason to avoid in-hospital births”  and “[t]he tradeoff of an increased risk of C-section for a small decreased risk in neonatal morbidity and mortality is not worth it for some women.”  He goes on to emphasize neonatal death risks, but says that women should be educated and assess trade-offs for themselves.

Oregon Health and Science University actually does offer some of the options that other OBs said hospitals should provide.  They have midwives on staff attending births, tout their low C-section rates (which actually aren’t that low, but are below 30%), and offer waterbirth and vaginal breech births.  Even though Caughey chairs the department at a hospital with many “home-like” options, he is the most open to the idea that some women might still choose to birth at home.

Obstetricians are the people most likely to see the rare birth disaster, and understandably, such emergencies make an impression.  Because even a low-risk birth can go wrong, many OBs see low-risk home births as risky, and Caughey pretty obviously believes hospital births are the better choice–which is absolutely his prerogative.  At least he doesn’t imply that women who make different choices than he would simply don’t know what they are doing.

Home and hospital births, however, are often compared to each other with little consideration of circumstances.  For instance, home-to-hospital transfer rates for women who have had a previous birth are far lower than they are for women having a first birth–in the largest home birth study done in the United States, transfers were three times more common among first time mothers–22.9%–vs. 7.5 % for women who had birthed before.  As mentioned above, the risk of an unnecessary C-section is very high at some hospitals and almost unheard of at others.  Some hospitals are not even equipped to do on-the-spot emergency cesareans, resulting in bans on vaginal birth after cesarean.  Thus, a woman might want to consider more than just home vs. hospital, but individual circumstances–does her pregnancy have elevated risk?  Does the hospital available to her offer evidence-based care?  What are the skill levels of the various practitioners available at the hospital or at home?

Even the Wax report acknowledges

Planned home births were associated with fewer maternal interventions including epidural analgesia, electronic fetal heart rate monitoring, episiotomy, and operative delivery. These women were less likely to experience lacerations, hemorrhage, and infections. Neonatal outcomes of planned home births revealed less frequent prematurity, low birthweight, and assisted newborn ventilation.

It is presumptuous for obstetricians to offer only neonatal death rates when giving women information about risks of home vs. hospital births. While the risk of neonatal death is a very serious one, it hardly ever happens.  Wax estimates the risk to be about 2/1,000 for home births vs. a little less than 1/1,000 for hospital birth.  On the other hand, a hospital with an 80% cesarean rate for low-risk births would give a woman an 800/1,000 chance of having a cesarean vs around 50/1,000 if she births at home.

Women take the lives of their babies very, very seriously.  It is almost certain that every mother loves her baby more than any obstetrician does.  With accurate facts about all aspects of birth, women are capable of doing their own risk assessments, and they have the right to choose even high risk home births, despite the opinion of you, an obstetrician, or anyone else who doesn’t agree with her choice.

For the record, I have eaten raw cookie dough all my life and am just fine, but you don’t have to have any.  As for the service project, we had bought pasteurized eggs, and all of the kids enjoyed cookie dough to their heart’s content.

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The Wall Street Journal published a piece on the ubermoms of Brooklyn who want to homebirth.  As a feature story, the piece made a number of interesting observations specific to New York, such as how birth noises might impact neighbors in tightly packed apartment buildings, potential issues with a hospital transfer for a laboring woman in a fifth-floor walk-up, and the desire for homebirth in the Orthodox Jewish community because Cesareans pose a risk to having large families.

Whenever homebirth is mentioned, people go berserk about risk.  The comments in the WSJ piece are full of lines like, “Please do not have you children at home… If someothing (sic) happens, you will live with your guilt for the rest of your life” ; and “People are fools.”  Others point out that women want to homebirth because the Cesarean rate in most New York City hospitals is around 40% and it is very difficult to have an intervention free labor and birth in these hospitals even if the there are no complications.

Two ways of considering risk are looking at relative risk and absolute risk.

Relative risk considers the risk of one choice vs. another.  For instance, your risk of choking to death on a piece of meat or a raw carrot chunk is much higher than your chance of choking on a spoonful of pudding washed down with a swig of Coke.

Absolute risk considers how likely it is that each event will actually happen.  Continuing with the example above, you might consider your risk of developing tooth decay vs. death by choking.  In considering such choices, you might ask, what is my  risk of dying by choking to death vs. my  risk of tooth decay?  You might decide that, though death is a very serious risk, the very tiny  risk of death is less serious that the much higher risk of tooth decay.

We make decisions with poor relative risk profiles all the time because the absolute risks are small.  Sometimes this is done for convenience; for instance, we often ride in cars rather than walking.  Sometimes we do it for pleasure; we might choose to go mountain climbing rather than staying at a nature center watching videos of mountain climbing.  And studies show that we often assess risk poorly, living in fear of rare events like school shootings and terrorist attacks while blithely driving or taking showers without a skidmat.

The article points out that relative risk statistics indicate that the chance of infant death is about three times higher in a home birth than in a hospital birth (this statistic, based on the infamous Wax study, has been widely disputed, but for the sake of argument, we’ll proceed as if it is accurate).  However, the chance of death during a birth is very, very small (statistics on neonatal death consider all deaths by 28 days after birth; infant mortality counts all infants who die in the first year of life–these are different statistics from deaths during birth or in the few minutes afterward).  According to the Wax study, among babies without birth defects, the chance of death at a homebirth was .15%, or 1.5 per 1000 births.  As statistician Marian F. MacDorman says in the article, “the absolute risks of home birth are very low, no matter how you slice it.”

Weigh that against the chance of a cesarean at a hospital birth (approximately 400 per 1000 according to the article; the World Health Organization says 150/1000 is a “threshold not to be exceeded”). And according to the article, the chance of unwanted birth interventions in the hospital is close to 100%, meaning almost 1000/1000.  These interventions can include everything from administration of Pitocin to continuous electronic fetal monitoring, to artificial rupture of membranes, all of which have risks of their own, especially when used without indication.

With honest information, a woman can decide whether the relative risk of death in homebirth vs hospital birth (if the statistic is even accurate) is worth the absolute risk of major abdominal surgery or of unnecessary intervention that can cause pain, infection, loss of autonomy, neonatal complications, or even maternal or infant death.  It is completely legitimate for a woman to make a decision based on her own assessment of the risks, and that includes her right to assume the risks of either home or hospital birth, as well as consideration of risk to herself as well as her baby.

Wall Street Journal article: http://online.wsj.com/article/SB10001424127887323639704579016902834439742.html

Wax study abstract (look at the results as well as the conclusion): http://www.ajog.org/article/S0002-9378(10)00671-X/abstract

Complete text of the Wax study: http://dhmh.md.gov/midwives/Documents/Wax-etal.pdf

Overview of critiques of Wax study: http://www.scienceandsensibility.org/?p=2551

World Health Handbook on Monitoring Obstetric Care (see p. 25):  http://www.who.int/reproductivehealth/publications/monitoring/9789241547734/en/index.html

Book about Americans’ poor risk assessment: http://www.amazon.com/Culture-Fear-Americans-Minorities-Microbes/dp/0465003362

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