December 19, 2011 | 1,094 Comments

Birthplace study yields additional disturbing information

The Birthplace Study, published just 3 weeks ago, is the largest, most comprehensive study of homebirth ever done. The authors summarized their findings as follows:

… [T]here was a significant excess of the primary outcome in births planned at home compared with those planned in obstetric units in the restricted group of women without complicating conditions at the start of care in labour. In the subgroup analysis stratified by parity, there was an increased incidence of the primary outcome for nulliparous women in the planned home birth group (weighted incidence 9.3 per 1000 births, 95% confidence interval 6.5 to 13.1) compared with the obstetric unit group (weighted incidence 5.3, 3.9 to 7.3).

In other words, the risk of death and serious injury was approximately double in the homebirth group and that increase was seen mainly among first time mothers.

There is a very significant limitation to this conclusion, however. The list of study exclusion criteria was far more restrictive than the actual exclusion criteria for homebirth in the UK. Therefore, a substantial proportion of the women who actually had a homebirth were excluded from the study even before it began. Of the 18,269 low risk women planning homebirth at the start of the study, 1346 (7.4%) were excluded from the study despite the fact that they went on to have a homebirth under the auspices of the National Health Service.

Fortunately, the authors of the study have published nearly a thousand pages of supplementary material. Buried in part 4 of the supplemental material is the outcomes for those women who had homebirths but did not meet the very restrictive criteria of the study. Outcomes are compared to the low risk women electing hospital birth who also failed to meet the more restrictive criteria for inclusion in the study. It is instructive to look at what happened in those births.

Not surprisingly, the incidence of adverse events was higher in the homebirth group, even when compared with higher risk women who delivered in the hospital.

Birthplace higher risk

The first thing to note is that in contrast to the women who did meet the rigorous exclusion criteria, in which 73% (12,050/16538) were multips, among those who did not meet the criteria, fully 83% (1096/1324) were multips. That’s not surprising when you consider that multiparous women were required to meet an additional level of scrutiny; specifically they had to have had no complications in any previous pregnancy.

Second, homebirth doubled the risk of an adverse outcome for both nulliparous women and multiparous women in the higher risk group. That’s not surprising, either. Disregarding outcomes of previous pregnancies makes the two higher risk groups more comparable to each other that the two lower risk groups are to each other.

This is just further confirmation of the central finding of the study. Homebirth, doubles the risk of adverse perinatal outcomes. Therefore, the claim of the Royal College of Midwives and other homebirth advocates that “.., [f]or women having a second or subsequent baby … homebirths appear to be safe for the baby” is not true.

Moreover, the more grandiose claim of homebirth advocates that “50% of women” could safely have a homebirth is a complete falsehood. The Birthplace study actually shows that homebirth is only safe in rigorously screened low risk multiparous women who in addition to having no risk factors in this pregnancy, have had no risk factors in any pregnancy.

In other words, homebirth is safe only when nothing goes wrong. To ensure that nothing goes wrong, candidates for homebirth must be screened very rigorously. Anything that could be remotely considered a risk factor in the current or any previous pregnancy renders homebirth unsafe.

The basic reality of childbirth, that it is inherently dangerous, and that life threatening events can happen without any warning, is confirmed by the Birthplace Study. Homebirth is safe only when nothing goes wrong. Since there is no way to predict with complete accuracy whether something is going to go wrong, homebirth can never be as safe as hospital birth.

Author:Amy Tuteur, MD

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