Post hoc, ergo propter hoc

If I remember my Latin correctly, this phrase means, “After this, therefore because of this.”

Many times, it is tempting and easy to use this logical fallacy to say that this or that was the cause of the reduction in deaths or disease. This happens all the time — even among people who should know better.

Take maternal mortality, for instance. This CDC document covers maternal mortality from 1915 to 2003. If you go to page 7 of the pdf file (p. 2 of the publication), you’ll see a graph that shows maternal mortality. Apologists for obstetricians are quick to point out that maternal mortality dropped in the 20th century from a high of nearly 1000 deaths per 100,000 live births to single digits by the close of the century. (However, the fact that maternal mortality is beginning to rise again, despite even higher obstetric intervention is not allowed to be mentioned. [But to be fair, some of the numerical rise is due to better reporting — which means that the double-digit figures are more accurate (but still underreporting), and also that single-digit figures were quite inaccurate.]) Pro-birth control folks are quick to point out that maternal mortality dropped after birth control pills became available and common. (The fact that there was a precipitous decline even before birth control began is not breathed.) Pro-abortion folks are quick to point out that maternal mortality dropped after abortion became legal. (The fact that most of the drop of maternal mortality happened well before legalization of abortion, and the fact that many deaths caused by abortion are ignored altogether or attributed to other factors or otherwise not officially linked to abortion, is verboten.)

Post-hoc fallacy, all of it.

Legal abortion has contributed somewhat to the official maternal mortality rate dropping, but if you’ll follow the links above you’ll see that much of the “official” drop is due to inaccurate reporting. Birth control has undoubtedly contributed somewhat, since women who don’t get pregnant are not counted in maternal mortality statistics. Obstetrics has contributed somewhat, since there are some women who are truly safer in the hands of high-risk specialists. But for any of these to claim the total credit is total bull. And post-hoc fallacy. It doesn’t take into account a great many other changes and advances in this world.

Look again at the graph on page 7 (and page 13 & 14 show the actual numbers, year by year). See how that there were fewer deaths at the beginning of the reporting period (1915) than in subsequent years, until the mid-to-late ’30s? Birth moved to the hospital during this time — at the turn of the century, most babies were born at home, with midwives attending; wealthier women could afford a doctor to attend them at home; but hospital birth did not become near-universal until the late ’40s or early ’50s, although it trended upwards from the early 1900s on, reaching the half-way mark somewhere in the ’30s.

Let me insert here, for lack of a better place, that I’m intentionally ignoring the huge spike in 1918, because I think a large part of that may have been due to influenza. I remember one of the Trivial Pursuit questions in the original game said that there were more deaths due to flu in that year than were due to World War I (either just in the U.S., or worldwide), so I’m assuming that a lot of these deaths were partially attributable to that.

So, from 1915-1933, birth was becoming more common in the hospital, but the maternal mortality rate was lowest in 1915, and did not drop below that level until 1934. If obstetrics made childbirth so much safer, the mortality rate should have steadily declined as birth moved from near-100% in the home (if home was so very dangerous) from before 1915 (I’m assuming it’s the earliest year data was collected) until the mid-30s. Instead, we see that it actually rose and fluctuated above the 1915 number. So, as birth moved to the hospital, more women died. (This website has a lengthy discussion of this time period, as well as numerous historical quotes from this time period, which show that obstetricians were aware that more women were dying under their care than under the care of midwives at home. Their answer? “We need to eliminate midwives, so that we’ll have more women to practice on and improve our care” — not a direct quote, but my paraphrasing of their arguments.)

While you may say that I’m engaging in post-hoc fallacy by linking increased maternal mortality to hospital birth, I don’t think so. The doctors of the time noticed it, and correctly attributed it to their poor handling of birth, but just assumed that they needed to make birth more surgical and standardized and sterilized, to surpass the midwives’ safety records. However, the average doctor’s training on births was appalling. Some of the critics of the day noted that the average doctor would start “delivering” babies after having merely seen perhaps only half a dozen births in med school, and maybe not even participating in any. Also, this CDC document includes the following quotes:

Inappropriate and excessive surgical and obstetric interventions (e.g., induction of labor, use of forceps, episiotomy, and cesarean deliveries) were common and increased during the 1920s. Deliveries, including some surgical interventions, were performed without following the principles of asepsis. As a result, 40% of maternal deaths were caused by sepsis (half following delivery and half associated with illegally induced abortion) with the remaining deaths primarily attributed to hemorrhage and toxemia (2).

The 1933 White House Conference on Child Health Protection, Fetal, Newborn, and Maternal Mortality and Morbidity report (13) demonstrated the link between poor aseptic practice, excessive operative deliveries, and high maternal mortality.

Going back to the first CDC document, you’ll notice that the year after that White House report was issued, the MMR dropped below the 1915 level for the first time. In the link I provided that had the quotes from obstetricians of the ’20s, you’ll see that one of the most influential OBs of the time recommended 100% episiotomy and forceps births — whether this was done under general anesthesia which can be dangerous and deadly unless performed under modern standards, or under twilight sleep (possibly dangerous, but haven’t heard any deaths directly attributable to it), I don’t know, but either of these could possibly have increased the death rate even without further medicalization of birth. But doctors assumed that with sterilized equipment and sterile hospitals, that these would be safe. They were wrong. Many women died due to infected incisions — incisions that they would not have gotten had they remained at home, uncut. Antibiotics were not first available until the mid-’30s (sulfa drugs), and then penicillin was introduced in the ’40s. You’ll see that after this time, maternal mortality began a steep and steady decline, so that by 1949, the MMR dropped below 100/100,000 for the first time. It was also around that same time that safe blood transfusion became possible, which also undoubtedly contributed to the reduction in deaths from maternal hemorrhage, since excess blood loss could be ameliorated by pumping in donor blood to keep these women alive.

Let me insert here that the MMR of many Third World countries is currently around the MMR for our country about 100 years ago. I think that is important, because if you look at what life is like for them now, and compare it to life in the U.S. in the early 1900s, you’ll see a lot of similarities — clean water, electricity, quick transportation, improved sanitation, drug knowledge and availability, etc., are things we take for granted that just weren’t there 100 years ago, nor are they widespread in much of the world today.

The thing that really prompted me to undertake this post was really a post by a vaccination blog that I read recently. If you go there, you’ll see a couple of graphs which show that mortality from various diseases (such as diphtheria) was in steep decline prior to the onset of vaccines. Yet vaccine proponents like to just zoom in on the rates for the year or two prior to the vaccine’s release, point to the drop after the vaccine, and say, “LOOK! That’s what the vaccine did!” When in reality, many times the decline in mortality actually slowed down after the vaccine’s introduction.

I’m not saying that vaccines are horrible and ineffective, but I do question the fear-mongering numbers that the vaccine proponents base their numbers on. Nor am I saying that obstetricians haven’t saved the lives of numerous women or children, because I believe they have. But I am saying that it’s a shallow assessment of what caused maternal mortality rates to fall — or infant mortality — or any other mortality, to point to one single factor that happened a century ago and say, “After this, therefore because of this.” I’ve seen doctors do this many times. They say, “Maternal mortality fell 99% in the 20th century, and hospital birth rose to 99%.” True enough. But obstetricians are not responsible for the entirety of that rate, which is what they seem to claim.

Here is a post which sums it up quite nicely: Who to Thank for Public Health Miracles. While obstetricians can rightly claim some of the reduction in maternal mortality, it’s a slap in the face to the many millions of people who contributed in less glamorous or less noticeable ways to the tremendous improvements we have in 21st century America. To put it bluntly, it took more than obstetricians to move this country from conditions not unlike those of current Third World nations to where we are now. A lot of other folks deserve most of the credit — from doctors who pioneered blood transfusions, safe anesthesia, and antibiotics; to lawmakers and others who spearheaded legislation and grass-roots efforts for clean and safe food and water; to men who made automobiles common, and quick and safe roads possible (both contributing to less horse manure in the streets and quicker transports to hospitals); to a whole heckuvalot of sewer workers and street sweepers and other “invisible” people who help make and keep this country clean. Let’s give credit where credit is due. Yes, obstetricians deserve some of the credit — but not nearly so much as they heap onto themselves! Sure, they can give blood transfusions, but obstetricians weren’t instrumental in creating safe blood transfusions, and other doctors could give them just as well. Yes, obstetricians can perform surgery with the patients under anesthesia or awake without pain, and with infection most likely able to be controlled, but they did not pioneer the anesthesia or analgesia, and had nothing whatever to do with the creation of antibiotics. They can do surgeries and properly prescribe drugs, but so can a lot of other doctors. And the fact that they can wash their hands in clean water and scrub their hands with disinfectant soap was not the invention of an obstetrician, but the work of many scientists and engineers who created the soap, as well as the machinery and the process by which nasty things are taken out of sewage and pure water is recovered and flows through our plumbing system.

Credit where credit is due — obstetricians are able to perform what they can by standing on the shoulders of a lot of “giants” as well as a lot of regular folks as well. To try to say that the 99% reduction in maternal mortality was the result of obstetrics alone is shallow, shallow, shallow! (Not to mention haughty, self-serving, and a lot of other negative adjectives I could throw out.) But it’s easier to say that than to say the truth, and try to tease out how the other factors (clean food, water, electricity, machines, antibiotics, blood pressure drugs, anesthesia techniques, etc.) contributed to the overall decline.

I will say this, I’m glad to live in a country where we have obstetricians. I just hope never to have to actually need one! 🙂 I know that birth is safer in America than it is in a lot of other places, and part of that safety is due to obstetrics. But not near the 99% that they claim it to be.


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