It may be worth working up a sweat while waiting for the stork to arrive.

A new study that took place in Madrid looked at the impact that exercise had on the health of hundreds of pregnant women.

It turned out the ones who had structured exercise had fewer issues with hypertension and weight gain than those who did not.

Michelle Mottola, a professor at Western University, collaborated on the study that has been published in the American Journal of Obstetrics and Gynecology.

The study involved two groups of nearly 400 women each. One was a group of women that took part in a structured exercise routine three times a week. The other was a control group of pregnant women, who received regular care from doctors during their pregnancies.

Mottola, who is the director of the R. Samuel McLaughlin Foundation Exercise and Pregnancy Lab at Western University, said the study found "important health benefits for both mother and baby" from the physical activity that the exercise group undertook.

The women who had frequent exercise "were more likely to prevent hypertension or high blood pressure during pregnancy and also they were more likely to prevent excessive gestational weight gain."

This group also saw fewer children being born at an excessive weight.

"What that means is that we can prevent chronic disease risk in both mother and baby in future," said Mottola.

In terms of the numbers, Mottola said the study found that women who don't exercise while pregnant are three times as likely to suffer hypertension and 1.5 times more likely to gain excessive weight. And they are 2.5 times more likely to give birth to very large babies.

"When you think about being physically active during your day and during your life, it's extremely important that the mother maintains a healthy lifestyle because that has a huge impact on both her and also for her unborn baby," said Mottola.

Staying active

Mottola believes pregnant women should strive for taking 10,000 steps each day while pregnant.

She said this is achievable by adding a daily walk to balance out any deficit from the amount they normally walk and that 10,000-step count.

Mottola said there are limits to how much exercise a woman should undertake while pregnant.

But there is a healthy level of activity, too.

"We do know that women who are medically pre-screened and follow the Canadian guidelines will have healthy pregnancies," she said.

"I think what we're more concerned about nowadays, especially with the obesity epidemic the way it is, is that maybe pregnant women are not being active enough."