Inducing labour may increase the risk of autism: study

Studies suggest that induced labour in pregnant women may raise the risk for having a child with autism, particularly if that child is a boy.


Many researchers including those from Duke University have cautioned that there are often overriding medical reasons to induce or augment labour that should not be ignored because of any potential risk of autism.


Inducing labour involves stimulating contractions before labour has started through various means, and augmenting labour refers to the practice of helping labour progress more quickly with oxytocin (Pitocin), a drug that stimulates contractions.


About one in 88 children born in the United States has autism, a spectrum disorder that affects behaviour and the ability to communicate, according to the US Centres for Disease Control and Prevention. There is no consensus on what causes autism, but several factors are thought to increase risk, including advanced maternal age and/or pregnancy complications.


In the new study, researchers looked at the birth records of more than 625,000 babies born in North Carolina between 1990 and 1998, and compared those with public school records to see who was later diagnosed with autism.


According to the researchers, 1.3 percent of boys and 0.4 percent of girls were diagnosed with autism. Specifically, boys born to moms whose labour was induced or helped along were 35 percent more likely to develop autism, compared with their counterparts. Among girls, only augmented labour was associated with an increased risk for autism. The increased risk of autism held even after researchers controlled for other factors such as the mother's age.


The new study, published online Aug. 12 in JAMA Paediatrics, is the largest to date that looks at autism risk and factors affecting labour and delivery. The findings don't prove that labour induction or augmentation cause autism, they just show an association. Exactly how labour induction could affect autism risk is unknown, but the drug oxytocin may play a role.


"The risk is significant, but it is not grossly significant," said study author Simon Gregory, an associate professor of medicine and medical genetics at Duke University in Durham, N.C. He said the autism risk posed by labour induction or augmentation is similar to the risk seen with advanced maternal age."Autism risk is likely a cumulative effect of many genes and many environmental effects," he noted.


The new results should not be interpreted to mean that helping labour along is a dangerous medical practice, Gregory stressed.