Any ideas? Thumb numbness

Si

For the past 2 weeks I’d say my thumb feels tingly. From about one inches above my wrist all the way to the tip of my thumb. Not any other fingers and only my left hand. Not necessarily numb or even painful. Just annoying and persistent. Certain movements make it worse and better. Is this pregnancy related? I’m 22 weeks. Never had anything like this. Could it be carpal tunnel? Any ideas?