Monday, August 25, 2008

Evidence based practice?

Homebirth advocates are always prattling about evidence based practice, and yet the practices that are most closely associated with homebirth midwifery have no evidence to support them. The following are axiomatic in homebirth midwifery today:

eating in labor
moving during labor
squatting at birth
delayed cord clamping.

Amazingly, not one of these practices is supported by the weight of scientific evidence. What is especially amusing is that organizations such as Lamaze go to the trouble of publishing papers that claim to support a particular practice, but actually do no such thing.

Consider what passes for "evidence" for Care practice #2: Freedom of Movement in Labor:
In fact, no woman who participated in any of the research studies said that she was more comfortable on her back than in other positions (Simkin & Bolding, 2004). No study has ever shown that walking in labor is harmful in healthy women with normal labors (Storton, 2007). One study published in The New England Journal of Medicine in 1998 did not find that women who walked had shorter labors; however, the women in the study who walked were so satisfied that 99% of them stated that they would like to walk again during future labors (Bloom et al., 1998).
In other words, no research has demonstrated any benefit, but none has demonstrated any harm. If the only thing to recommend a particular practice is that it doesn't harm anyone, should it really be elevated to a cornerstone of care? I'm not suggesting that women shouldn't be allowed and encouraged to move freely in labor, but based on the scientific evidence, it does not appear to make any difference.

How about Care Practice #5: Spontaneous Pushing in Upright or Gravity-Neutral Positions. Once again this is a cornerstone of contemporary homebirth midwifery practice, and once again there is no evidence to support it:
According to the Cochrane Pregnancy and Childbirth Group, a respected international organization that defines best practices based on research, the use of any upright or side-lying position, compared with supine or lithotomy positions (lying on back, legs supported by stirrups), is associated with the following results:

* shorter second stage of labor;
* a small reduction in vacuum or forceps-assisted birth;
* fewer episiotomies;
* less chance that the woman will report severe pain;
* fewer abnormal fetal heart rate patterns;
* a small increase in second-degree lacerations (in the upright group only); and
* an increase in estimated blood loss, although there was no evidence of serious or long-term problems from the extra blood loss (Gupta, Hofmeyr, & Smyth, 2004).
In other words, it really makes no difference.

As I have discussed in the past, there is no evidence that eating in labor improves labor outcomes and there is evidence that it increases the risk of maternal death from the rare complication of maternal aspiration. Also, as I have discussed in the past, there is no evidence that delayed cord clamping provides any benefit except perhaps in premature babies, who are prone to anemia. Indeed, there is evidence that active management of the third state of labor, which includes early cord clamping, improves maternal outcomes by decreasing the risk of postpartum hemorrhage.

Claiming that at least it doesn't harm anyone, or if it harms someone it only does so occasionally, is hardly an evidence based justification for these practices that are integral to contemporary homebirth midwifery.

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