Friday, July 13, 2012

Western Australia has a 20-fold increase in hypoxic deaths at homebirth

Another day, another database showing an appalling homebirth death rate.

The latest evidence comes from The 13th Report of the Perinatal and Infant Mortality Committee of Western Australia for Deaths in the Triennium 2005–07 full report (here). This report includes the most comprehensive analysis of homebirths yet in Western Australia. In the wake of the 12th report, which showed that homebirth in WA had triple the perinatal death rate of hospital birth, the Perinatal and Infant Mortality Committee was charged with more than identifying homebirth deaths. The Committee was charged investigating the cause of preventibility of homebirth deaths.

The results are truly appalling AND entirely consistent with the terrible homebirth death rate in the US. The major finding is that homebirth QUADRUPLED the risk of perinatal death compared to hospital birth. Indeed, homebirth dramatically increased the risk of death at every level, from stillbirth to infant death.

Keep in mind these statistics UNDERCOUNT the risk of death. That's because there may have been deaths that occurred in the hospital that actually belong in the homebirth group. Moreover, the comparison is between homebirth and all hospital births (including high risk and premature births). To understand the full magnitude of the problem, homebirth deaths should be compared to low risk hospital birth, not all risk hospital birth.

In the wake of the 12th annual report that showed homebirth tripled the perinatal death rate, the Committee was charged with determining the causes of perinatal deaths at homebirth, and whether the deaths were preventable. Once again, the results are nothing short of appalling:

The greatest discrepancy in mortality risks for planned home births compared to planned hospital births was in deaths due to peripartum hypoxia. There were 28 perinatal deaths attributed to hypoxic peripartum insult in the 2005-07 triennium (24 in planned hospital births and 4 in planned homebirths). The risk ratio for stillbirth attributed to peripartum asphyxia was 21.5 times higher for the planned home birth group compared to the planned hospital group. The risk ratio for infant death due to peripartum asphyxia was 18.2 times higher for the planned home births compared with planned hospital births...

The Committee also assessed whether the homebirth deaths were preventable. Of the 7 homebirth deaths:
Four of these cases were coded as ‘hypoxic peripartum deaths’ ... They occurred in term or post term pregnancies. These four cases had preventable medical factors (preventability scores >=2) and three were considered potentially avoidable deaths (preventability scores >=4). The proportion of deaths in planned home births with preventability scores >=2 was 57.1%, which was higher than the proportion of 10.3% of all investigated deaths with preventability scores >=2. The proportion of potentially avoidable deaths with preventability scores >=4 was 42.9% in planned home births and 2.4% of all investigated deaths.
To summarize, the WA data show that the risk of perinatal death at homebirth is quadruple that of hospital birth; the risk of perinatal death at homebirth due to hypoxia is approximately 20-fold higher than hospital birth; and, 51.7% of the homebirth deaths were potentially preventable compared to 10.3% of the hospital deaths.

The Committee made the following recommendations:
a) Home births are associated with preventable stillbirths and infant deaths. Midwives offering home birth services should obtain informed consent from women to acknowledge that they have been informed of the increased risks of perinatal death associated with home birth.

b) A formal independent audit of implementation of the Recommendations of the Review into Homebirths should be performed. This audit of practice should encompass all home births, whether the midwife is under the auspices of the Community Midwifery Program (CMP) or is independent.

c) There are insufficient data about morbidity associated with homebirth in WA. A prospective cohort study to assess mortality and morbidity outcomes for women with planned home births in WA should be arranged as a priority. This cohort study should be performed by an independent group of researchers.
This is yet another stream to add to the growing flood of information on the dramatically increased risk of perinatal death at homebirth. In addition, this data confirms that the primary cause of homebirth deaths is hypoxia (lack of oxygen) and that most of these deaths are preventable.

The strength of this data lies in the fact that the deaths themselves were analyzed, both for cause and for preventablity. Does similar data exist for American homebirth? Indeed it does. The Midwives Alliance of North America (MANA) the group that represents American homebirth midwives, has assembled a data collection far larger than that of Western Australia. The MANA database contains 18,000 homebirths and has been analyzed for cause of death. What does it show?

We don't know because MANA is hiding that data. MANA performed an analysis similar to that of Perinatal and Infant Mortality Committee of Western Australia and almost certainly obtained a similar (or possibly far worse) result. The state of Western Australia made their results public in an effort to reduce the death rate from homebirth. MANA refuses to make their results because in an effort to hide the death rate from homebirth. The WA Committee is concerned with the health and well being of newborns; MANA is concerned only with its own reputation.

This piece first appeared on The Skeptical OB in February 2011.

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