Although I’m normally not much of a napper, that changes during my pregnancies. Without fail, it became virtually impossible for me to keep my eyes open when 3 o’clock rolled around during my third trimester. But rather than fight the urge to lay down for a quick doze, a new study gives pregnant mamas full permission to get a little shut-eye—for the health of their babies.

According to new research published in the journal Sleep Medicine, pregnant women who regularly nap are less likely to have a baby with a low birth weight, defined as weighing less than 5.5 lbs. A low birth weight is associated with health complications during childhood and adulthood, such as respiratory illnesses and hypertension. So snoozing doesn’t only help you get through the afternoon, but also has some potentially big benefits for the long-term health of your baby.

For the report, researchers in China analyzed data from 10,111 participants in the 2012-2014 Healthy Baby Cohort study. They found that expectant mothers who regularly took afternoon naps between 60 and 90 minutes long were 29% less likely to have a baby with a low birth weight compared with mothers who didn’t nap. They also found that napping five to seven days a week reduced the likelihood of having a baby with a low birth weight by 22%.

The findings are significant to Dr. Suzanne Karan of the University of Rochester Medical Center in New York. Although she wasn’t involved in the study, she tells Reuters Health that her team is investigating a link between babies’ birth weights and mothers’ sleep habits. “This napping study is another signal that paying attention to sleep is an important part of your overall pregnancy health,” Karan says. “Pregnancy is like a stress test that shows what health problems you could have later in life, so it’s important to pay attention and treat it now.”

If that isn’t compelling enough, keep in mind that pregnancy fatigue is caused by the physical and hormonal changes your body is undergoing while growing a human. On top of that, nighttime sleep may be more disrupted by bathroom breaks and physical discomfort by the third trimester.

And while the new study found the biggest benefits among mamas who logged more than an hour of napping, even a power nap can go a long way toward filling your energy tank—so go ahead and snooze without the guilt.