07/31/2025
Recently, investigators published the results of a large randomized controlled trial* evaluating whether induction in the first 4 days of week 38 would reduce the incidence of shoulder dystocia (the head is born, but the shoulders hang up behind the p***c bone) when the baby was suspected of being large for gestational age compared with waiting until at least 39 weeks 4 days. The takeaway from the trial making the rounds is that induction at 38 weeks did, indeed, reduce the incidence of shoulder dystocia.
Did it?
Dr. Sara Wickham’s analysis of trial outcomes concludes:
“The main report of The Big Baby Trial highlights one marginal result while other important outcomes have been underexplored, ignored, or relegated to the supplementary data. It’s almost as if the authors so badly wanted the research to show a benefit to induction that they have interpreted the results in favour of induction even where the actual data don’t support this.”
Read her take down of the trial to find out more about its many flaws and weaknesses, to which I’ll add two more:
1) While shoulder dystocia is concerning, it is not in itself an adverse outcome. Almost all shoulder dystocias will be resolved without incident, and on the rare occasions when a complication results, almost all of those babies will make a complete recovery.
2) We don’t know the extent to which typical labor management provokes shoulder dystocia by such practices as pushing and delivery while lying on the back.
* Gardosi J, Ewington LJ, Booth K, et al. Induction of labour versus standard care to prevent shoulder dystocia in fetuses suspected to be large for gestational age in the UK (the Big Baby trial): a multicentre, open-label, randomised controlled trial. Lancet 2025;405(10491):1743-56.
https://www.sarawickham.com/articles-2/bigbaby/