One More for the "Leave Birth Alone" Files
By Rachel Walden — October 31, 2007
The Cochrane Collaboration has released a new systematic review on amniotomy (artificially breaking the waters, or “artificial rupture of membranes”) for speeding up labor which concludes that the current evidence does not support the practice. It is important to note that this paper is not a new randomized controlled trial (the “gold standard” for evidence in medicine), but compiles the findings from fourteen studies of a total of 4,893 women, and presents a recommendation on the practice based on a review of these previous works. The Cochrane Collaboration, however, is regarded as one of the most reliable sources of systematic reviews, which allow the comparison of evidence from multiple studies and provide a “big picture” view of the topic.
Amniotomy is often used because it is believed to shorten the duration labor, or speed it along when it has become “prolonged.” The authors of the Cochrane review concluded that:
“The evidence showed no shortening of the length of first stage of labour and a possible increase in caesarean section. Routine amniotomy is not recommended for normally progressing labours or in labours which have become prolonged.”
Regarding c-section, the reviewers found no statistically significant difference in cesarean rates, but because the finding was nearly significant, they indicated that they could not say with certainty that rates are not increased when amniotomy is performed.
The reviewers found that amniotomy appeared to make no difference in length of the first stage of labor, maternal satisfaction with the childbirth experience, use of pain relief, oxytocin usage, postpartum hemorrhage, or maternal or perinatal morbidity or mortality (serious complications or death). As such, their final recommendation was as follows:
“Implications for practice: On the basis of the findings of this review, we do not recommend that amniotomy be introduced routinely as part of standard labour management and care. We do recommend that the evidence presented in this review should be made available to women offered an amniotomy and may be useful as a foundation for discussion and any resulting decisions made between women and their caregivers. It may be useful to provide information to women as part of their antenatal education.”
The full-text of the paper is not available without a subscription, but a brief summary is available, as is a short piece in the New York Times.
While a randomized controlled trial is the gold standard for advancing new knowledge, a systematic review, such as the Cochrane Review, is more and not less powerful for shifting practice. A single RCT may achieve its results by virtue of the peculiarities of its population, unrecognized biases of study design or implementation, or even chance (our standard for significance leaves us certain that one in twenty are by chance). A proper systematic review provides greater certainty than a single RCT.
Lynette, thank you very much for your comment. As a clinical medical librarian by profession, I especially appreciate your points about single RCTs, and agree with you 100% about the potential limitations of those trials, especially in applicability to the broader population.
I also agree with you about the ability of systematic reviews to synthesize and evaluate the evidence, and as such giving more weight to a practice or idea, but I think your emphasis on a “proper” systematic review is very important. It’s important to be diligent in the evaluation of any type of publication, although, as I suspect you know, the Cochrane Collaboration is generally very, very good at this sort of thing.
The distinction between RCTs and systematic reviews was made in this piece because many readers don’t spend their days immersed in medical research. So often in the media, we simply see things referred to as “a study,” with no discussion of the specific type or strengths and weaknesses, so I like to make the distinction as an educational point, not necessarily an aspersion on the piece at hand.
Was that too much medlib wonkiness for one comment? 🙂