Originally posted at Grounded Parents
Trigger Warning for talk regarding neonatal mortality.
The relative risks of homebirths versus hospital births is an extremely contentious subject. Previous research, mostly done in European countries has shown an extremely small or even nonexistent risk of newborn death from homebirths relative to hospital births, however until recently there have been almost no good studies looking at the risks of homebirths for mothers in the U.S.
This week on the Skepchick backchannel, Julia mentioned that a new study was released this month by the Journal of Midwifery & Women’s Health on the safety of homebirths in the US. This study is being touted by Midwifery organizations as confirming the safety of homebirths. Julia also shared with us this post by Dr. Amy Tuteur from the Skeptical OB where she makes the claim that this same study, which supposedly shows how safe homebirths are, actually shows a 450% increase in newborn death rates from homebirths and confirms how unsafe homebirths really are. Like Julia, I had trouble understanding how two different people can look at the same study and yet come to completely opposite conclusions as to the results, so I thought it might be an interesting area to turn my statistical eye.
The main crux of Dr. Tuteur’s argument is the following:
According to Citizens for Midwifery:
The overall death rate from labor through six weeks was 2.06 per 1000 when higher risk women (i.e., those with breech babies or twins, those attempting VBAC, or those with preeclampsia or gestational diabetes) are included in the sample, and 1.61 per 1000 when only low risk women are included. This rate is consistent with some published reports of both hospital and home birth outcomes, but is slightly higher than others.
No, it isn’t “slightly” higher. It is MASSIVELY higher.
According to the CDC Wonder database, the neonatal death rate for low risk white women at term from the years 2004-2009 is 0.38/1000. As Judith Rooks, CNM MPH noted in her review of Oregon homebirths, intrapartum death among low risk babies is essentially non-existent in the hospital, so the neonatal + intrapartum death rate for the hospital is still 0.38
As the chart above demonstrates, the MANA death rate for the same years was 5.5X HIGHER. In other words, the MANA death rate was 450% higher than the hospital death rate.
She also includes this chart comparing the various death rates:
I clicked the link Dr. Tuteur gave where she got the Citizens for Midwifery quote but didn’t see anything with that quote or numbers on the linked page. I did download and read the study which these numbers supposedly came out of, though it’s worth noting that Dr. Tuteur wrote her post prior to the full paper being released.
I’m not really sure exactly where this quote came from and these numbers don’t seem to match anything in the study. My best guess is that the quote came from a press release or results summary. The stats she mentions (2.06 per 1000 risk of death for all births and 1.61 per 1000 risk of death for low-risk births) are not mentioned anywhere in the actual study, though that doesn’t mean they are not accurate.
Page 7 of the study lists the following fetal and neonatal mortality rates for the homebirth sample:
Intrapartum fetal death (after onset of labor but prior to birth): 1.30 per 1000
Early neonatal death (death after birth in first 6 days of life): 0.88 per 1000
Late neonatal death (death between 7 to 27 days after birth): 0.41 per 1000
However, these numbers include all births in the sample, not just to those of low-risk women. The study also listed the following mortality rates for births excluding lethal congenital anomaly-related deaths:
Intrapartum fetal death: 1.30 per 1000
Early neonatal death: 0.41 per 1000
Late neonatal death: 0.35 per 1000
These numbers still include high-risk births such as breech or twins, though. I was unable to find a low-risk birth stat comparable to the one Dr. Tuteur mentions in her post. I was hoping the stats she mentioned would be in the study so I would get some good confidence intervals to work with, but instead I’m just going to have to take Dr. Tuteur at her word and have to interpret the numbers without confidence intervals.
It’s worth mentioning here as well that the study in question did not compare risks in homebirths to that of a comparable hospital birth cohort. Instead, all this study did is look at a sample of almost 17,000 planned homebirths in the US in which they had lots of detailed information and then report on various statistics about those births.
Let’s leave this study for a bit and go back to the numbers Dr. Tuteur cites in her post. According to Dr. Tuteur, 1.6 per 1000 low-risk planned homebirths from the recent study resulted in neonatal death within 6 weeks of birth. Using CDC data, she also determined that the risk of neonatal death for low-risk white women in the US during the same years was 0.4 per 1000 births. She then points out that OMGZ YOU GUYS THAT’S A 5.5X INCREASE IN BABY DEATHS!
Continue reading at Grounded Parents…