Last year a friend of mine found out she was pregnant. She’s one of those women who are naturally slim and never seems to have trouble with weight gain. It took her months until she started to show her baby bump but it seemed like one day she was as thin as ever and the next she was carrying around a little rotund tummy. This is pretty natural for some women, but others seem to gain their baby weight more gradually. However, new research also suggests that in some cases a consistent weight gain can be associated with pregnancy risks such as autism spectrum disorder (ASD).

The weight gain though, is generally more than most women typically gain during pregnancy. The new research from the University of Utah doesn’t indicate that weight gain causes autism, but rather it can be a symptom that may indicate an underlying problem. Previous studies have linked high birth weight and high prenatal weight to the development of ASD, but this study examines the maternal side of the pregnancy and suggests that gaining more weight than usual at a steady rate might also indicate ASD as well.

The lead author of the study was Dr. Deborah A. Bilder, and an assistant professor of psychiatry at the University of Utah. She commented that "The risk of autism spectrum disorder associated with a modest yet consistent increase in pregnancy weight gain suggests that pregnancy weight gain may serve as an important marker for autism's underlying gestational etiology. These findings suggest that weight gain during pregnancy is not the cause of ASD but rather may reflect an underlying process that it shares with autism spectrum disorders, such as abnormal hormone levels or inflammation."

The moderate difference in pregnancy weight and the relationship between ASD was previously found in two prior studies. This study sought to provide more evidence. A group of 128 children aged eight participated in the study along with a control group of 10,920 children of the same age and gender of the other group. For further comparison, a group of 288 children of the same age with diagnosed ASD were also invited to participate so that their research could be compared against their siblings that were unaffected by ASD.

With both groups of ASD affected children, many of the mothers were found to have slightly abnormal weight gain during pregnancy, though only with their children that developed ASD. This small but consistent finding suggests that small weight changes during pregnancy could share an underlying cause with ASD. The mother’s BMI at the beginning of pregnancy didn’t seem to be linked to ASD.

Source: University of Utah Health Sciences (2013, October 28). New study examines link between pregnancy weight gain, autism spectrum disorders. ScienceDaily.