Moms who do this before and during pregnancy have babies who develop faster

Talk about prenatal gains.

A new study out of Japan shows that women who prioritize one common activity during pregnancy might be giving their babies a developmental advantage.

After assessing nearly 40,000 mothers and children, the researchers found that babies raised by moms who were physically active before and during pregnancy were more likely to hit developmental milestones early, especially in their first year of life.

Dr. Rosa Cui, an assistant professor in obstetrics and gynecology at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell Health, told The Post that the study is “intriguing” because it’s one of the first of its kind to consider the effects of exercise on neurological development during pregnancy.

In general, exercise is mostly a net positive for the body, she said. It’s good for the heart and other vital organs and can be beneficial for the mental and physical well-being of pregnant women.

And while the research doesn’t reveal exactly why physical activity during pregnancy helps the baby, Cui has several theories.

The first has to do with the impact exercise has on our blood vessels, opening them up as our muscles get warm and increasing overall blood flow to the body. 

“As a result of these blood vessel changes on a very, very microscopic scale, that potentially might increase the blood volume and the blood and the nutrients and oxygen and all the good things that are delivered to the uterus for the baby,” said Cui, who was not affiliated with the new study.

Another theory is that exercise decreases inflammation in the body, which can also affect a baby. 

Lastly, and maybe most intuitively, it’s possible that exercise is essentially just shaking everything up, stimulating the fetus’s sensory neurons purely through movement.

Regardless of how it works, it appears to have an overall positive effect.

Still, not every pregnant woman has the same abilities or needs, and an exercise regimen that works for some won’t work for others.

Cui generally recommends 20 to 30 minutes a day of “moderate intensity exercise” or activity that feels “just a little bit hard.” 

“Most of the time, for low-risk, uncomplicated pregnancies, people can continue to do that,” she said.

This can include walking, jogging, swimming, yoga, biking and even strength training. (Sadly, the 8-pound being you’re carrying around in your belly apparently doesn’t count.)

Not recommended? Skydiving, scuba diving, hot yoga and anything that qualifies as high-intensity.

One facet of the study, published Tuesday in JAMA Network Open, that Cui found especially interesting was that the benefits of a mom’s exercise routine during pregnancy seemed to only be noticeable during the baby’s first six to 12 months.

After that, it was hard to distinguish whether it was the exercise or other social factors that contributed to the babies’ brain development.

For example, being enrolled in group childcare by age 3 majorly benefitted babies’ communication skills, problem-solving abilities and social interactions.

This is good news for women who — depending on their medical history or current complications — have pregnancies that can’t accommodate much physical activity at all. 

Before starting any new exercise regimen, pregnant patients should consult their doctor, Cui advised.

“For people who are motivated to exercise, who already exercise, there’s benefit there that we can see,” Cui said.

“But if people cannot [exercise] for medical reasons or for personal reasons, there’s not that sense of immense guilt because it seems like other things that enrich the child’s environment will also have benefits in terms of their neurodevelopmental state.”

Babies are, after all, “very, very malleable” — and a few extra squats here and there during pregnancy likely won’t determine the rest of their life outside the womb.