I won’t lie: When I was pregnant with my now-toddler son, I barely worked out. At the time, I was attending grad school, which meant long days in class and hours lugging around video equipment. I was too tired to do anything more than walk the many flights of subway stairs to and from school.

Of course, my son is happy and healthy. But I do regret not exercising just a bit more during my pregnancy. Why?

Because new research confirms that staying in shape while pregnant has lasting benefits for your baby and you.

A new Medical Journal of Australia study found the prevalence of overweight and obese pregnant women has increased steadily over the last 25 years while, at the same time, so has the percentage of poor maternal and infant health outcomes. This suggests a rise in pregnancy obesity is leading to negative health outcomes for mamas and their little ones including gestational diabetes, heavy birth weight, and preeclampsia, according to the researchers.

The team of University of Sydney researchers analyzed health data from over 40,000 first-time mothers in a 25-year period and found that the proportion of overweight and obese pregnant women rose by nearly 7%. Conversely, the number of pregnant women within what’s considered a healthy BMI range dropped by more than 5%.

Senior author Kirsten Black, a professor of the University of Sydney, says, “As a consequence of that, we saw a rise in a whole range of adverse outcomes such as Cesarean sections, prematurity, gestational diabetes, stillbirths, fetal abnormality, preeclampsia and fetal macrosomia [larger than average baby]."

The findings from the new Medical Journal of Australia study supports evidence that exercise during pregnancy can benefit you and your baby's health. Staying active can improve sleep, build strength, boost your mood and reduce problems such as swelling and constipation.

Regular exercise while pregnant is also linked to a lower birth weight, lower maternal and fetal resting heart rates and a reduced risk of gestational diabetes, which the U.S. Centers for Disease Control and Prevention estimates impacts 9.2% of pregnant women.

Black and her research team, though, recognize that many women can’t stay active during pregnancy or have a harder time maintaining a healthy pregnancy weight. Black suggests doctors work with women to lose weight prior to pregnancy in order to reduce the risks of maternal obesity and poor health outcomes.

"There are a range of conditions for which women should be advised on around pregnancy,” Black says, “so we need to also ensure that there is greater access to preconception care.”

She adds, “It's important so that we can raise the issue in a way that women are able to find their own solutions, they're not dictated to, and they don't feel judged.”