No evidence that labour epidurals cause autism

A study, based on data of nearly 150,000 births from a single integrated healthcare system in the US, shows a possible association between the use of epidural pain relief in labour for women who deliver vaginally and an increased risk of autism spectrum disorders in their children. Such a finding is of obvious concern and research is urgently required to clarify the actual relationship between use of epidural analgesia in labour and autism.

Because the study is retrospective, what it does not and cannot show is a causal relationship. Indeed one of the surprising aspects of this study is lack of data about pregnancy and delivery complications which are known to increase the risk of autism. Such complications as prolonged duration of labour, fetal distress, fetal malposition and assisted vaginal delivery are also known to be associated with an increased request rate for epidurals. It is possible therefore that birth complications are actually the hidden factor linking epidurals and autism.

Why the authors excluded women in labour who required Caesarean delivery is not explained. We know that babies born by Caesarean section have a higher rate of autism, but they could have controlled for this in their analysis. This exclusion means that probably 30-35% of women who birthed during this period were not analysed.

The differences in patient characteristics between those having labour epidurals and those who did not may be an issue: for example, those who selected epidural analgesia were more likely to be from higher socioeconomic groups. Lower socioeconomic status is widely recognised to be associated with under diagnosis of autism. Children not enrolled with the health insurance scheme by one year of age were excluded. Again it is very possible that these were from lower socio-economic groups and had they been included the results may have been different.

It is important we do not forget that as well as being the single most effective form of pain relief in labour, epidural analgesia has safety advantages for both mother and baby. As far as the woman is concerned, epidural analgesia reduces the need for general anaesthesia. There are obstetric conditions where epidural analgesia reduces risks for both mum and baby.

This study cannot answer the mother’s question of “How likely is having epidural analgesia to damage my baby.” not least because it is limited to those who deliver vaginally and route of delivery cannot be guaranteed in advance.

This study should not alter the analgesia currently offered to women in labour.