Sick of morning sickness? Mothers-to-be can take heart from a new study suggesting that children born to women who suffered from nausea in pregnancy may be smarter.

The study, published in Thursday's online issue of the Journal of Pediatrics, found that children born to women who had been nauseous and vomiting during pregnancy performed better on a number of tests used to assess IQ and mental acuity. 

'When somebody's suffering through eating those saltine crackers [in the] mornings, they [can] just think of this as being a really good thing as opposed to a negative thing.'— Dr. Tina Chambers

Further, the study found that children born to women who took the drug diclectin for pregnancy-related nausea did not have lower scores than children whose mothers didn't use the drug to control morning sickness.

"A lot of women are still afraid to treat their morning sickness because of the fear of medications, often with very severe costs on their health," said senior author Dr. Gideon Koren, director of the Motherisk Program at the Hospital for Sick Children in Toronto.

"They can be dehydrated, they cannot work. Poor quality of life. So in a way this study further supports them and empowers them to treat themselves."

Koren and colleagues wanted to look at whether there were any signs that using diclectin during pregnancy was harmful. The drug has been on the market in Canada for decades, but was pulled from production in the U.S. about 25 years ago over concerns it might be harmful to fetuses. It is being reintroduced in that market.

The concerns, which came to light after the thalidomide scandal, led to the drug being extensively studied, said Dr. Tina Chambers, a teratologist at the University of California, San Diego's School of Medicine. Teratology is the study of abnormal fetal development, congenital malformations and what causes them.

Chambers said the evidence overwhelmingly supports the notion that the drug is safe for use in pregnancy and this study adds further weight to the argument.

But in studying the drug, Koren and his colleagues also looked at the children of women who refused treatment for their morning sickness and found that they scored higher on tests than children whose mothers didn't suffer from nausea during pregnancy.

Koren was quick to add that while the difference was statistically significant in scientific terms, it doesn't mean that the children whose mothers weren't nauseated were developmentally slow. Rather, it was just that the other children scored a bit higher.

Hormones from placenta

It's long been known that while hard to endure, nausea is actually a sign of a healthy pregnancy. Women who suffer from morning sickness are less likely to miscarry and less likely to give birth to babies with congenital cardiovascular problems.

The thinking is that some hormones secreted by the placenta — hormones needed for a healthy pregnancy — trigger the nausea.

And this work suggests they may have a positive effect on neurodevelopment, said Koren.

Chambers, who was not involved in the work, said the study only raises this hypothesis; it can't prove it. But she said it makes sense, biologically, and a study to prove it can probably be designed.

"It's really a fascinating finding," she said, adding it may help nauseated mothers-to-be soldier on.

"When somebody's suffering through eating those saltine crackers [in the] mornings, they [can] just think of this as being a really good thing as opposed to a negative thing."