Home birth is more dangerous. Discuss.

How dangerous is too dangerous?

We don’t prohibit all dangerous behavior, or even behavior that endangers others, including people’s own children.

Question: Is the limit of acceptable risks to which we may subject our own children determined by absolute risks or relative risks?

Case for consideration: Home birth.

Let’s say planning to have your birth at home doubles the risk of some serious complications. Does that mean no one should do it, or be allowed to do it? Other policy options: do nothing, discourage home birth, promote it, regulate it, or educate people about the risks and let them do what they want.

Here is the most recent result from a large study reported on the New York Times Well blog, which looks to me like it was done properly, from the American Journal of Obstetrics & Gynecology. Researchers analyzed about 2 million birth records of live, term (37-43 weeks), singleton, vertex (head-first) births, including 12,000 planned home births (that is, not including those where the home birth was accidental). They also excluded those at freestanding birthing centers.

The planned-home birth mothers were generally relatively privileged, more likely to be White and non-Hispanic, college-educated, married, and not having their first child. However, they were also more likely to be older than 34 and to have waited to see a doctor until their second trimester.

On three measures of birth outcomes, the home-birth infants were more likely to have bad results: low Apgar scores and neonatal seizures. Apgar is the standard for measuring an infant’s wellbeing within 5 minutes of birth, assessing breathing, heart rate, muscle tone, reflex irritability and circulation (blue skin). With up to 2 points on each indicator, the maximum score is 10, but 7 or more is considered normal and under 4 is serious trouble. Low scores are usually caused by some difficulty in the birth process, and babies with low scores usually require medical attention. The score is a good indicator of risk for infant mortality.

These are the unadjusted low-Apgar and seizure rates:

homebirthoutcomesThese are big differences considering the home birth mothers are usually healthier. In the subsequent analysis, the researchers controlled for parity, maternal age, race/ethnicity, education, gestational age at delivery, number of prenatal care visits, cigarette smoking during pregnancy, and medical/obstetric conditions. With those controls, the odds ratios were 1.9 for Apgar<4, 2.4 for Apgar<7, and 3.1 for seizures. Pretty big effects.

Two years  ago I wrote about a British study that found much higher rates of birth complications among home births when the mother was delivering her first child. This is my chart for their findings:

Again, those were the unadjusted rates, but the disparities held with a variety of important controls.

These birth complication rates are low by world historical standards. In New Delhi, India, in the 1980s 10% of 5-minute-olds had Apgar scores of 3 or less. So that’s many-times worse than American home births. On the other hand, a number of big European countries (Germany, France, Italy) have Apgar<7 rates of 1% or less, which is much better.

A large proportional increase on a low risk for a high-consequence event (like nuclear meltdown) can be very serious. A large absolute risk of a common low-consequence event (like having a hangover) can be completely acceptable. Birth complications are somewhere in between. But where?

Seems like a good topic for discussion, and having some real numbers helps. Let me know what you decide.

24 Comments

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24 responses to “Home birth is more dangerous. Discuss.

  1. In the US, the c-section rate is around 30% (http://www.cdc.gov/nchs/data/databriefs/db124.htm). To compare like with like, it’s necessary to compare women giving birth at home with similar women giving birth in hospitals. However women experiencing long labours in hospitals are typically given c-sections, hence are out of this sample, which only includes vaginal deliveries. I would want better numbers before making any kind of policy recommendations.

    It’s interesting that the effect goes away for second births.

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    • On the other hand, some women planning home births who experience or anticipate complications opt for a hospital birth, taking them out of the home birth sample. Also, on the selection question, of course women having c-sections sometimes have medical issues that led to that decision. Anyway, it looks to me like the % rate of Apgar <7 is lower for uncomplicated c-sections than it is even for uncomplicated vaginal hospital births: http://www.sciencedirect.com/science/article/pii/S0002937810000827 (paywalled). I don't think it's wrong to exclude c-sections if the question is the outcome of birth procedures, as c-section is a very different procedure.

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    • In looking at the numbers, the complication and adverse event numbers are really quite low. I think they’re low enough that it would not at all be irresponsible for a woman to make the decision to give birth at home if there are other intangible benefits that go along with that. A .13% increase chance of a below-4 Apgar and a .5% increased chance of an adverse event for a first birth is well within the variation you would see between hospitals. I wouldn’t choose it for myself; I had an excellent hospital birth and the quick access to care in the event of an emergency gave me peace of mind, but I don’t think the numbers justify any kind of policy change.

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  2. Thought you might be interested in this two-part series on some of the flaws in the research you cite in this post: http://mana.org/blog/25/guest-post-at-science-sensibility-on-home-birth-safety-research

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  3. Healthy families are more important than healthy babies. Childbirth is not just about the baby, but about the mother and the family. Absolute risk should determine what is acceptable. There will always be something that is “less risky.” But relative risk cannot guide every decision, because there are other factors to consider.

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  4. Kate G

    I am wondering about Apgar measurement issues. Hospitals are ranked/judged on birthing outcomes, so it seems like there may be an incentive to give higher Apgar scores. I know a surgeon that talks about docs fudging with surgery outcomes a bit to make their stats look better because it is very competitive, and hospitals/OBs are competing too…I would guess this incentive structure is not really there for a home birth midwife. Might be nice to see the numbers over time if they were out there.

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    • I don’t buy that. Don’t home birth midwifes have reputations to manage? If they are sued, won’t they want to show their great results from previous deliveries? The motives are the same. Also, I’m afraid this is impugning the integrity of the dedicated healthcare professionals who deliver babies in hospitals. You think they’re going to allow a conspiracy to cook Apgar scores? I don’t.

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  5. Based on anecdotal evidence, it seems to me that the percentage of women who end up having unplanned c-sections in the hospital is greater than the percentage of women who plan a home birth and end up going to the hospital. So Philip, I don’t have numbers for this, but I’m not convinced that excluding both groups from the study is a wash. Given the very high rate of c-sections in U.S. hospitals, it seems to me that it would be more representative to compare all hospital births (c-section + vaginal) to all home births, across a sample of women of the same age, health, and culture (some cultures in the U.S. more routinely have low-intervention maternity practices and women from these cultures may be better mentally and physically prepared for such). In determining acceptable risk, I would also want to see data on maternal mental and physical health and recovery time, birth experience, continued infant health beyond the first five minutes (including immune system development), and family health following each kind of birth. Everything I’ve mentioned together would give me a better basis for determining acceptable risk than just (potentially fudged) Apgar scores.

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    • Apples to apples isn’t always possible, and I’m sure these selection issues are more complicated than I know. But I actually think 5-minute Apgar is good for a close comparison of birth methods — that is, if you have to pick one discrete event to isolate. Once you get into how people are doing a week or two, or a month or two, later, you’ve got a lot more confounding factors you can’t control. That’s life. Unless you actually randomize people and do a controlled experiment. Even if you could convince a couple hundred people to do that (good luck), you need thousands to detect significant differences with negative outcomes this rare (fortunately). So, that’s out!

      Given the unknowns, my preference is for a legally-required license for people offering deliveries. Bus drivers need licenses.

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      • Apgar may be a decent marker, but I maintain that you’d have to include the Apgars of cesarian babies in the study, since just going to the hospital means there’s a 30% (some say 30 – 40%) chance you’ll have a cesarian. Having given birth twice, I do not judge any decision a woman makes about which interventions to use! But I would be interested to see the Apgars of babies who are born after admission of pitocin, epidurals, and by cesarian. Also, midwives need to be licensed, as well. Some practice without them, but some people drive vehicles without licenses, too.

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  6. I meant that midwives already are required to have licenses to practice in most places.

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    • And another thing …🙂 Apples to apples may not always be possible, but then the study should not purport to be comparing apples to apples if it isn’t. As I recall, Philip, is it usually you brilliantly calling people out on that kind of thing!

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      • What I meant was, I think the Apgar thing is a good way to get as close to apples-to-apples as possible. It’s not the whole story of home birth versus hospital birth, but it seems like a good picture of part of the story – medical outcomes of the birth process. Are people happier and healthier a year later as a result of home birth? This study doesn’t answer that.

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        • Here are the questions that come to my mind about the Apgar comparison:
          a) As I previously asked, how would this study look if it included Apgars for cesarian babies that could have been born vaginally had the hospital had a different tolerance for length of labor?
          b) Where, when, and from what standard was the Apgar test developed? Are there things that tend to happen differently in a home birth that may slightly affect the initial Apgar reading but actually have no detrimental effect – or may have a positive effect – on the baby’s actual chances for survival past the first five minutes? Longer labors, for example, might produce a more tired baby 5 minutes out, who might respond a little differently to the indiscriminately applied Apgar test, but extra blood cells build up in baby’s body during a long labor; these cells help sustain the baby through its first hours, particularly if there is hardship during birth or immediately after. Forget a year out, Philip; no one has convinced me yet that Apgar is the most accurate blanket predictor for a day out.
          c) How in this day and age can a study like this concern itself with maternal and family health ONLY as one of many control variables going in, and not as part of the subject — a part that is affected by the method/location/practitioner’s approach to the birth? Maternal birth experience, recovery, and health immediately after birth can be central to a baby’s actual survival in its first days, weeks, months — not to mention the survival of the family during that time. Sorry, but this study’s extremely limited view of “medical outcomes” is not cutting it for me.

          To my lay eyes, this study seems beset with flaws in approach and method; I’m surprised that you are not applying your usual academic skepticism. I’m not sure what you mean when you mention policy change. I am very much in favor of policy change — change that normalizes the option of home birth, makes it easier for licensed midwives to get insured and therefore makes home birth with an experienced, licensed midwifery team cheaper, safer, and more accessible. Change that encourages conventional medical cooperation with midwives so that emergency transfers to hospitals, and midwifery in hospitals, can be done in the way that best benefits the birthing mother and her baby. How about change that removes the financial motivation for hospitals to be birthing factories? Then we’ll see how many studies come out about the benefits of home birth.

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      • Quick reply to Jessi –
        1. I posted a link above to a study showing that uncomplicated c-section babies have very low rates of bad Apgar tests, so I don’t think excluding them is why the hospital birth rates are low.
        2. I am not buying that Apgar is some kind of biased, pro-hospital test with fudged results. The other study linked above shows that bad Apgar scores are a very good predictor of infant mortality in the first year. If you look at the list of indicators it measures, it’s pretty hard to cook up a logical reason why having a low score would be better.
        3. I like the idea of improving insurance coverage, support for midwife training, and better integration with Big Med when necessary.

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  7. Thanks to the people taking issue with the data in this study. Sadly, I’m a lazy researcher and have nothing to say with any data to back me up. So I’ll just say: bullshit.

    I am curious about the women chosen for this study – post-30, US-based white women that likely have health insurance or can afford the expense of a homebirth midwife, in the US anyway, it ain’t cheap.. Is the study to provide these women proof for why they need to avoid perils of homebirth? Make it harder for midwives to practice outside of hospitals? it’s very strictly regulated. Have hospitals noticed a drop in the middle-aged lady birthing market and need it debunked? All that really survives in this is the title – another vote for fear and conventional hospital birth. Like they need the advertising.

    The hospital birth model is only recently awakening to the wisdom of a midwife attendant model of birth and attempting to imitate it. Let’s hope the trend continues, but as it tries to catch up, why drag down the wisdom of ages of female-centered medicine? Giving birth at home does work – a lot of the time, but it just doesn’t seem to be able to command the press. I’m not believing the bad outweighs the good.

    Apologies for my unsupported rant. But, hell, it is a blog afterall🙂

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    • Thanks for ranting!

      One problem with the wisdom of the ages of female-centered medicine was the astronomical death rates of mothers and their children. I’m sure there were benefits. Whether the bad outweighs the good is a question above my pay grade. Some people would surely say that living a long life is not worth it if it means subjecting yourself to modern medicine. In the long run, the difference of a few decades in life expectancy is dwarfed by the scale of time. I’m not being sarcastic. My obsession with survival rates and life expectancy over other outcomes reflects my conformity. And of course lots of modern medicine doesn’t make people live longer or better lives.

      On home births I’m definitely not saying the bad outweighs the good. And I hope I’m not spreading irrational fear. But based on what I’ve seen I am convinced that the birth process itself is more dangerous at home. But that shouldn’t (and won’t) deter people who think there are very important benefits from home birth. I’ve had some great experiences doing things that carried risks. Hell, some people still smoke cigarettes, and some drive cars, which are both very dangerous things to do.

      The whole point of the post was to provoke thinking about how to compare things that are hard to compare but that we have to compare, like a 0.5% risk of something bad versus the perceived benefits of home birth. And lo, that’s the conversation we’re having.

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  8. poetisa16

    If you look on page 4 of the study, it says that planned home births attended by certified midwives had similar outcomes to in-hospital births, with the difference that the latter were more likely to result in NICU admission. So I would say that real issue with planned home birth is the need for access to a quality birth attendant, which by the way is not guaranteed in a hospital birth either. I think framing the issue as “choosing a home birth could be dangerous for your baby” is irresponsible given that the presence of a trained, skilled, experienced, and supportive birth attendant providing continuous care is a very important factor no matter where you’re giving birth.

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  9. Kate

    The stats on these are so complex. I don’t particularly have an axe to grind in this debate, but I must say the figures surprise me. People have fairly successfully populated the earth and whilst I agree there were a lot of problems and high maternal and neonatal mortality rates before modern medicine, they aren’t the births included in these stats. The problem births have been largely taken out. I’m a vet and the births I’m least likely to have to get involved in are the all the other mammal equivalents of home births from healthy animals. I’m not so sure we’re completely different to every other mammal.

    For example – if we imagine this is explained by home birth mothers being less likely to have caesarians. Then we must remember that the long term implications of c sections for babies are not inconsequential. Caesarian is associated with increased risk of allergy and asthma. Caesarian babies are likely to be born with good APGAR scores as they have quick births with lots of paediatricians ready to provide oxygen so they are pretty good by five minutes, but if they are at increased risk of anaphylaxis are they actually getting a good outcome? I’m not sure. Integrating all the relative risks of all the long and short term outcomes would be complex. Another aspect is maternal outcomes – if women are having more interventions they are having a worse birth outcome, how do we include that factor.

    Finally, I don’t know to what extent we are comparing similar things, babies born in hospital have poor outcomes associated with low APGAR scores but it really might by different at home. These studies have been done in hospital where low APGAR scores are related to things like instrumental assistance at birth (forceps or ventouse) whilst neither of these can occur at home. We have been studying hospital births since the post war period, home births for healthy well fed women with medical back up are, perhaps surprisingly, rather unknown quantities.

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  10. Though birth certificate data is reliable on some variables, it is notorious for being incomplete. When Frank Chervenak, second author on the paper, presented a preliminary version of this paper at the Institutes of Medicine workshop on birth settings, Marian MacDorman, a senior statistician and researcher in the Reproductive Statistics Branch at the National Center for Health Statistics, took him to task. You can see Chervenak’s presentation here:

    http://www.iom.edu/Activities/Women/BirthSettings/2013-MAR-06/Day%202/Panel%207/39-Chervenak-Video.aspx

    and MacDorman commenting in the follow-up here:

    http://www.iom.edu/Activities/Women/BirthSettings/2013-MAR-06/Day%202/Panel%207/42-Panel-Discussion-Video.aspx

    I don’t know much about the other authors on the paper, but Chervenak is virulently anti-homebirth. Seizures seems like an odd choice given all of all the data on the birth certificate–I would bet it was cherry picked because it fit the author’s preconceived conclusions. I work with birth certificate data myself, and it is notoriously unreliable on most data fields, both because it is often not completed and because in hospital births, the person filling it out doesn’t actually know the patient.

    I have a number of blog posts about this.
    Here is one about homebirth risk:
    http://humanwithuterus.wordpress.com/2013/08/27/homebirth-wall-street-journal-style-and-considering-risk/

    And here is one about the ways in which women are controlled and punished while birthing in hospitals:
    http://humanwithuterus.wordpress.com/2013/09/04/permission-and-punishment/

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