Fortunately, muscle relaxers are safe during pregnancy. As you can imagine, pregnancy can take a toll on your muscles—your weight increases and your center of gravity changes. What used to be minor muscle spasms can sometimes get really intense, most commonly in your back.
Cyclobenzaprine (Flexeril) is the most commonly prescribed muscle relaxer. It’s considered pregnancy category B1 , meaning animal studies are reassuring but no real human studies have been done. (FYI, no pharmaceutical companies directly study medications on pregnant people.)