Mothers who suffer morning sickness during pregnancy have better chances to bear smarter babies, Canadian scientists have found out.

Researchers at Toronto's Hospital for Sick Children's Motherisk Program have discovered that morning sickness appears to be linked to enhanced neurodevelopment of the fetus.

For the study, 121 pregnant women were recruited between 1998 and 2003 through a morning sickness hotline run by the Motherisk program.

Participants were split into three groups: mothers who experienced morning sickness and were treated with diclectin (a drug used to treat nausea and vomiting during pregnancy); those who experienced morning sickness and did not take diclectin; and those who did not experience morning sickness.

The intelligence and behavior of the children of those pregnancies were then assessed when the kids were three years old and seven years old. The kids were given age-appropriate psychological tests, including measures of intelligence and behavior.

Other factors such as mother's IQ, number of cigarettes smoked per day, alcohol consumption and socioeconomic status were also taken into account.

The study found that all children across the three groups scored within the normal ranges for neurodevelopmental outcome. But the children of women with morning sickness scored higher on performance IQ, verbal fluency, phonological processing and numerical memory.

Remarkably, the more severe the morning sickness, the more likely the children were to earn higher scores, the researchers found. They noted that maternal IQ also played a role in the outcome.

The results appear in the online edition of The Journal of Pediatrics.

Morning sickness, which affects as many as 80 percent of pregnancies, is often one of the first signs of pregnancy, typically beginning around the second week of pregnancy. Many doctors speculate it is the result of altered levels of hormones, such as estrogen, HCG (human chorionic gonadotropin), and thyroxine.

While previous studies have focused on how pregnancy queasiness affects the outcomes of pregnancies, this is the first study to look at the long-term effects of the nausea on the cognitive skills of the babies that result.

Dr. Gideon Koren, the principal investigator of the study and the director of the Motherisk Program, said the hormone swings that lead to morning sickness nausea are actually a good thing.

"It's the hormones secreted by the placenta that cause you to feel yucky, but on the other hand, they probably confer better conditions for the baby," he told Canadian Television Thursday.

"Women suffer for it, but at least it's for a good cause," he said.

(Xinhua News Agency April 24, 2009)