Introduction and hypothesis: This study aimed to evaluate any differences in the incidence of perineal trauma in women undergoing vaginal delivery following intrauterine fetal death (IUFD) versus live-births. This information would be of interest in evaluating the possible effect of fetal demise on the mechanism of labour in the second stage and thus may provide invaluable insights to contribute to our understanding of the impact of fetal tone on the mechanics of labour and delivery.
Methods: 323 women who delivered vaginally following IUFD were matched with 1,000 women with a live-birth for age, parity, gestation and birth weight. Women undergoing assisted vaginal delivery and/or episiotomy were excluded.
Results: Women with an IUFD had a significantly lower risk of perineal trauma overall (relative risk 0.16) as well as a lower risk of obstetric anal sphincter injury specifically (RR 0.12).
Conclusions: Women delivering vaginally after IUFD have a lower incidence of perineal trauma compared with women delivering a live infant. This may be due to differences in biomechanics following an IUFD.