New Insights into Pregnancy and Autism
Most experts agree that autism, a condition affecting 1 in 88 children, is likely due to a complex mixture of genetic factors and environmental exposures during early development. The bulk of autism research to date has focused on studying autism in early childhood. In recent months however, emerging evidence has pinpointed that an earlier period in our lives, the time spent in the womb, may also have a substantial influence. This critical period of time, from conception to birth, is both a time of rapid growth and also vulnerability for the developing baby.
A recent study suggests that an abnormal immune system in an expectant mother could result in an autistic child. The study, involving more than 3000 women, found that mothers with an autistic child are four times more likely to have “brain-reactive antibodies” in their blood. Normal antibodies are proteins produced by the immune system to help the body fight infection. “Brain-reactive antibodies” are antibodies that act on a person’s own brain tissue, potentially telling the immune system to target the brain. The concern is that during pregnancy the mother’s “brain-reactive antibodies” could travel across the placenta and bind to the baby’s developing brain.
Whether or not this brain binding results in damage remains controversial. Even though this study demonstrated the link between the antibodies and autism, it could not prove that these antibodies cause autism. Yet, just establishing this link is important, as other studies are also highlighting how events in the womb are connected to autism.
Although we cannot spontaneously change the way the immune system works, we can make efforts to optimize prenatal care and diet. There is evidence that prenatal folic acid may be protective against autism. A recent study found that mothers who used folic acid prior to conception or in early pregnancy had a 40 percent decreased risk of having a child with autism. Additionally some research suggests that ensuring an adequate intake of omega-3 fats may also be important. One study noted that pregnant women who had very low omega-3s in the diet had a 50 percent greater risk of autism in their children.
Further evidence of the importance of the womb environment arises from research on valproate, a medication used to control seizures and treat bipolar disorder. Valproate is generally avoided in pregnancy as there is long standing evidence of it leading to spinal cord problems in children. The use of valproate by pregnant mothers has also been linked to an almost three-fold increase in autism in their children.
Finally another recently reported finding that found women who had an induced labor had an increased autism risk in the baby. It is however unclear whether this association is due to the medications used to induce labor, or the fact that complicated pregnancies are more likely to lead to induction in the first place. But, we must also recognize that induced labor has benefited many women by substantially decreasing baby deaths.
The problem remains that all of these research studies struggle with one thing: causality. They cannot prove what they are studying actually causes autism, partly because of the way these studies are designed. There may also be a large number of other, interacting factors that increase autism risk in pregnancy, and these studies are likely to only be assessing the tip of the iceberg. However, the evidence is certainly growing that what happens in the womb may have serious consequences, including some cases of autism. This may be particularly pertinent in women who are at higher risk, such as those who have a child already diagnosed with autism or a history of autism in the family.
We already know that exposure to smoking, alcohol, and a range of medications during pregnancy can result in conditions such as fetal alcohol syndrome, low birth-weight, or can increase the chances of attention hyperactivity deficient disorder (ADHD) in children. Given the emerging evidence, it is therefore reasonable to also suggest what happens in the womb during pregnancy may also affect the likelihood of having an autistic child.
We need to continue to research these links but in the meantime we can rely on some basic principles. Women who are trying to conceive or who are pregnant should follow the advice of their physician, obtain good prenatal care including folic acid supplementation, consume a healthy balanced diet, and avoid both alcohol and tobacco.