Sudden blood pressure drop

I have been going in for NSTs twice per week. I’m 32 weeks pregnant. My blood pressure at my last appointment on Monday was 103/80.

Today (Thursday, 3 days later). It was 99/67. That just seems like kind of a big drop to me and my blood pressure has always kind of hovered around 105/75.

I brought it up to the doctor but she didn’t seemed concerned. But idk I feel like that kind of a drop is unusual. Anyone ever have this happen. Is it concerning or no?