Yesterday I gave a brief overview of the new MANA statistics paper (Homebirth midwives reveal death rate 450% higher than hospital birth, announce that it shows homebirth is safe) and pointed out that the fact that MANA waited 5 years to release the results demonstrates that Cheyney at el. have known for years that their death rates are hideous. It took them that long to figure out how to spin a death rate more than 5.5 X higher than comparable risk hospital birth as “safe.”
Today I’d like to take a closer look at the many deceptions, large and small, that Cheyney and colleagues have employed in writing a paper that has a conclusion directly opposed to the actual evidence.
But before we look at what Cheyney et al. wrote, it is helpful to consider what we need to know to make a determination of safety.
1. We need to know how many babies of the nearly 17,000 intended to be born at home actually died.
2. We need a comparison group. In this case, because we are looking at presumably low risk white women, ages 20-44, at term, with babies that are not growth restricted, the appropriate comparison comes from the Linked Birth Infant Death Files collected by the CDC. The database is publicly available on the CDC Wonder website. The death rate for the years 2004-2009 is 0.38/1000.
3. We CANNOT compare homebirth to out of date studies.
4. We CANNOT compare homebirth to other countries since the populations are quite different.
5. We CANNOT remove congenital anomalies from the homebirth group unless we also remove them from the hospital group.
6. We CANNOT assume that the fact that a baby died of a congenital anomaly at home means that it is a “lethal” anomaly. Many anomalies that inevitably result in death at home are highly treatable in the hospital.
7. We cannot remove breech, twins, VBAC, and other high risk conditions from the homebirth group because homebirth midwives are publicly on record claiming that these conditions are “variations of normal” and have lobbied across the country to have them included in homebirth midwives scope of practice.
When we compare the death rate at homebirth of 2.06/1000 with the CDC death rate for low risk white women, ages 20-44, at term, with babies that are not growth restricted of 0.38, we find that homebirth has a death rate 5.5X higher than hospital birth. In other words, the death rate at homebirth is 450% higher than comparable risk hospital birth. A third way of expressing this finding is as follows:
4 out of 5 babies who died at home could have been saved in the hospital.
In simple terms, the bulk of the MANA stats paper is a bald faced attempt to bury these results by inappropriately removing groups that should be included and then inappropriately comparing the results to papers from other countries.
At various points in the paper, Cheyney et al. remove congenital anomalies, remove breech, twins and VBAC. They proceed to compare the result to homebirth papers from the Netherlands and Canada. They ignore the CDC death rates for comparable risk white women during the same years; indeed, to read the paper, you wouldn’t know that the CDC death rates exist.
Their conclusion:
If you inappropriately remove anomalies, breech, twins and VBAC and compare the results to homebirth studies from other countries, our results aren’t that much worse; ergo homebirth is “safe.”
Cheyney at al. do provide data that should give everyone pause:
Of the 22 fetuses who died after the onset of labor but prior to birth, 2 were attributed to intrauterine infections, 2 were attributed to placental abruption, 3 were attributed to cord accidents, 2 were attributed to complications from maternal GDM, one was attributed to meconium aspiration, one was attributed secondary to shoulder dystocia, one was attributed to preeclampsia-related complications, and one was attributed to autopsy-confirmed liver rupture and hypoxia. The causes of the remaining 9 intrapartum deaths were unknown.
So out of 22 babies who died during labor (compared to a predicted rate of zero deaths in the hospital), 13 died of preventable causes. They died because they were too far from the personnel and equipment who would have saved them.
For the 7 newborns who died during the early neonatal period, 2 were secondary to cord accidents during birth (one with shoulder dystocia), and the remaining 5 were attributed to hypoxia or ischemia of unknown origin. Of the 6 newborns that died in the late neonatal period, 2 were secondary to cord accidents during birth, and the causes of the remaining 4 deaths were
unknown.
So out of 13 babies who died in the neonatal period, at least 9 died of preventable causes. They died because they were too far from the personnel and equipment who would have saved them.
In other words, out of the 35 homebirth babies who died, at least 22 died of obviously preventable causes.
The death rates in certain subgroups were astronomical.
(5 fetal/neonatal deaths in 222 breech presentations), TOLAC (5 out of 1052), multiple gestation (one out of 120), and maternal pregnancy-induced comorbidities (GDM: 2 out of 131;
preeclampsia: one out of 28
The authors are honest about the primary methodological limitation of the study. Data collection was voluntary and only 20-30% of CPMs contributed:
The main limitation of this study is that the sample is not population-based. There is currently no mandatory, reliable data collection system designed to capture and describe outcomes for all planned home births in the United States.We are also unable, for a number of reasons detailed elsewhere, to quantify precisely what proportion of practicing midwives of various credentials contributed data to MANA Stats between 2004 and 2009…
It is highly likely, therefore, that the 450% elevated death rate dramatically UNDERCOUNTS the real risk of homebirth.
Nonetheless, we can reach important conclusions. Despite the fact that the authors surveyed only a small proportion of practicing midwives, who submitted data that was not validated, and despite the fact that they authors performed a variety of maneuvers that violated basic standards of statistical analysis, and despite the fact that they were intent on concluding that homebirth is “safe” regardless of what the data showed, they actually showed that homebirth has a minimum rate of death 5.5X higher than comparable risk hospital birth.
We can also be sure that the authors understood that their data showed that homebirth has a horrifically high death rate, because they try to hide the number of deaths for the past 5 years, released the data only under pressure, and then proceeded to draw a conclusion entirely at odds with what their own data showed.
In addition, we can also conclude that homebirth is NEVER appropriate for breech, twins or VBAC.
Finally, we can come away from the paper with the horrifying realization that MANA has absolutely no idea what its own members are doing. There is no systematic attempt to determine if they are safe practitioners. To hear the authors tell it, they can’t even figure out how many practicing CPMs are actually submitting statistics, let alone whether those statistics are accurate.
When it comes to the safety of homebirth, the only question remaining is:
Who are you going to believe, MANA or your own eyes?
Homebirth midwives reveal death rate 450% higher than hospital birth, announce that it shows homebirth is safe.
Why did the Midwives Alliance of North America wait 5 years to publish its statistics?
