In recent weeks, it seems we’ve been asked this question more and more frequently by our pregnant clients. It’s overwhelming to try to take in all of the information about the risks and benefits of medical interventions during labor and delivery, and even more challenging when there is only a small number of high quality academic studies available to guide our choices.
An individual’s risk of perineal tearing during vaginal delivery is based on a myriad of factors, some under our control (such as birthing position and the use of hands-on perineal support techniques) and others not (such as the size of the baby and speed of delivery). The choice to have epidural anesthesia is also dependent on a patient’s medical history, personal values and prior experiences, and often the duration and intensity of labor. However, more and more of our clients are basing this choice, at least partially, on whether an epidural will change their risk of perineal tearing with delivery.
Many studies attempt to separate the effect of variables such as the use of an epidural on risk of perineal tearing. The most recent analysis (Pergialiotis 2014) combined the data from 22 studies with a total of 651,934 subjects. Its conclusion was that those with epidural anesthesia had a 1.95 times greater risk of perineal tearing than those who did not. However, another large single study of 61,308 women showed that in its subjects, the increased risk of tearing with an epidural was not present when the analysis controlled for the fact that more first time mothers choose an epidural, and a first vaginal delivery is also more highly associated with perineal tearing.
Take away: One study shows that epidurals increase the risk of tearing. Another says that the reason more tearing occurs with epidurals is that more first time moms choose epidurals and first vaginal deliveries are already associated with a higher risk of tearing.
That’s a lot of statistical analysis to digest, but the short story is that, as with many things in medicine, it is almost impossible to draw definitive conclusions. However, we can definitively say that there has not yet been a study that shows that epidurals decrease the risk of perineal trauma with birth - only that it may increase it or not affect the outcome at all. Our advice to clients is to make choices regarding anesthesia based on other important risks or benefits, but to avoid using risk of tearing as the single deciding factor.