Saturday, 18 June 2016

Treatment for pre-term rupture of membranes in pregnancy

Another large international trial is published, and another standard practice based on little more than our bias towards doing something rather than doing nothing is reversed.

Sometimes the membranes rupture early in pregnancy. They are meant to rupture at or near the time of delivery (at term) but they occasionally rupture early. When they rupture very early in pregnancy, the treatment is to wait because the risk of harm from delivering a premature baby is high. When they rupture close to term, the treatment is to deliver the baby as the risk of doing so is low, and there is a risk of infection if we do not.

The grey zone is the immediate ‘pre-term’ period, between 34 and 37 weeks of pregnancy. Here, many clinical guidelines and recommendations from professional societies recommend immediate delivery, but this is not based on good evidence, and practice varies considerably.

The PPROMT trial, which was published in the Lancet in 2015 (here, paywall sorry) randomised nearly two thousand pregnant women in centres spread across many countries to either expectant treatment (wait and see, and hopefully deliver the baby at term) or immediate delivery.

The researchers found that the caesarean rate and the complication rate were higher in the immediate delivery group. There was no difference in the infection rates or infant mortality (3 in each group). They recommend NOT delivering the baby when the membranes rupture pre-term.

The bottom line
The desire that doctors have to intervene when there is doubt or uncertainty is strong. The desire to resolve that uncertainty by scientific inquiry is weak. Yet often, when the assumption that intervening is somehow ‘safer’ or a better bet than doing nothing is tested, the intervention often turns out to be no better, or, as in this case, worse than doing nothing. Once again, a problem that could have been solved much earlier if interventions were required to have evidence before we made recommendations about their implementation.

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