Sounds like alopecia areata. Definitely see you Dr. They may refer you to a dermatologist. Treatment is usually a topically applied steroid. Not sure about that while pregnant. There's a lot of gloom and doom about AA online. I had it in two spots. Both grew back fully within 6-8 months. Never had it since. Stress was the trigger. Biotin is a good supplement to help regrowth. Again, check on heavy loading that while pregnant...
Hubby had one and the barbershop lady told him to apply some oil but from Hispanic or Mexican store n it's full of hair now he can't find the or tell wher was the bald spot... he was told it was from stress
Maybe stress have you been stressing lately. Plus your hormones. alopecia areata is just hair loss in a certain spot. My hubby got one went in and they said it was nothing bad. But you should make an apt with your reg physician to get answers.