Statistics professor challenges midwives' math on home birth safety

Recently a group of midwives published a paper about birth outcomes for home births, which seemed to indicate home birth is as safe as hospital birth. A skeptic blog got a statistics professor to analyze the paper, and came up with very different results. Check them both out!

Midwives Alliance of North America, or MANA, has recently released data on over 16,000 home birth outcomes. A group of PhDs and midwives analyzed the data and concluded, in a paper published in the Journal of Midwifery and Women's Health, that "Low-risk women in this sample experienced high rates of normal physiologic birth and very low rates of operative birth and interventions, with no concomitant increase in adverse events." This conclusion has come under fire by some, including Dr. Amy Tuteur, a doctor, a blogger, and a skeptic about the safety of home birth.

Tuteur has been criticized in the past for the fact that she analyzes papers on hospital and home birth safety, but has not published an academic paper or had specialized training in statistical analysis. After this home birth paper came out, Tuteur asked Dr. Aviva Romm, a doctor and home birth advocate, to agree to an analysis of the paper by an independent statistician. Romm subsequently withdrew from the agreement, citing an insulting blog entry written by Tuteur.

Dr. Brooke Orosz, a statistics professor with several published mathematics papers and a YoutYube series about statistics, volunteered to analyze the paper. Orosz took a look at the MANA data, compared it to data from the CDC and WHO, and came to a very different conclusion, stating:

So, for a comparable group of infants born in the hospital, with congenital abnormalities excluded, the combined neonatal and intrapartum death rate is at most 0.7 per thousand. The combined neonatal and intrapartum death rate for the MANA STATS group, with congenital abnormalities excluded, was 2.06 per thousand, which is significantly higher. (p<.0001, highly statistically significant.)

In other words, the expected number of deaths from causes other than congenital anomalies was at most 12, and the actual number of deaths was 35 (44 with anomalies included). It is clear that home birth substantially increases the risk of neonatal death and of intrapartum death.

The paper goes on to analyze the difference between rates of mortality in subgroups of babies, morbidity in babies, and maternal mortality, and finishes:

The mothers in the MANA STATS cohort experienced fewer childbirth interventions than comparable-risk women giving birth in the hospital.

However, the rate of intrapartum stillbirth or neonatal death was considerably higher, and the difference was particularly alarming among high-risk subgroups such as breech and VBAC. The incidence of low APGAR was significantly higher and may have been much higher. The risk of postpartum hemorrhage was substantially higher.

This is an apparent contradiction of the conclusion published in the Journal of Midwifery: "no concomitant increase in adverse events." That leaves the ultimate conclusion up to the reader of both analyses. Check out both theJournal of Midwifery & Woman's Health paper, and Doctor Orosz analysis, published on The Skeptical OB, and decide. It's worth looking through the comments of Orosz's analysis, as Orosz responds to questions and talks about how her analysis of the paper affected her opinion on home birth.

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