Now they tell me.

I had terrible morning sickness — unrelenting nausea — during the early months of both my pregnancies. Ugh. I wouldn’t wish it on any woman.

Well, maybe I should wish it on them. A Canadian study published recently in the Journal of Pediatrics found that women who suffer morning sickness during pregnancy may be more likely to have a child with a few extra IQ points.

In fact, the worse the mother’s symptoms, the greater the chances of her child being brainy.

According to the study’s authors, this is the first study to determine the direct impact of morning sickness on children’s neurodevelopment.

One of pregnancy’s puzzles
Morning sickness is quite common, affecting at least half of all pregnant women. Its symptoms — nausea and, sometimes, vomiting — are usually strongest in the morning and tend to lessen as the day progresses. The nausea can begin as early as the second week of pregnancy and usually goes away by week 12 or so. For some women, however, the queasiness lingers throughout the pregnancy. For a very few (about 1 percent), the vomiting becomes severe enough to cause dehydration, weight loss and other problems for the pregnancy.

Why women experience morning sickness has long puzzled scientists. Theories abound. Some scientists believe morning sickness results from pregnancy-induced fluctuations of two hormones, human chronic gonadotropin (HCG) and thyroxine— fluctuations that are needed to help the placenta nurture the growing fetus.

The study
For this current study, researchers at Toronto’s Hospital for Sick Children recruited 121 women. They divided them into three groups: women with morning sickness who were taking the anti-nausea medication diclectin; women with morning sickness who were taking nothing for it; and women who were nausea-free.

When the women’s children reached the ages of 3 to 7 years, they were given age-appropriate psychological tests, including ones that measured intelligence. The mother’s IQ, socioeconomic status, and alcohol and cigarette use (all factors known to affect a child’s IQ) were also duly noted.

The results: All the children scored normal on the tests, but those whose mothers endured morning sickness — even if they resorted to taking diclectin to relieve their symptoms — were found to have IQ scores that averaged three to four points higher.

The results suggest an association between morning sickness (perhaps the higher levels of HCG and thyroxine) and improved brain development in the child, the study’s authors concluded.

Caveats
OK. Before you mothers who got through pregnancy without the morning heaves start feeling that you somehow let your child down, be aware that this study has several limitations. First, it was an observational study, and those kinds of study designs can’t prove cause and effect. You need a randomized blinded study for that. Second, the study was small. It involved only 121 women.

And third, the IQ differences could perhaps be explained by something that happened after birth. More research is needed.

In the meantime, moms, don’t worry. We all know that Minnesota children are above average.