I personally would be uncomfortable getting it pregnant. I didn't have the whooping cough jab or the flu jab with either of my children - mostly due to my own disorganisation and the hospital not having a clear way to book anything. But still, given that I'm a SAHP and therefore can be as cautious as I like (i.e. don't have to go to work every day on grotty Tube or deal with customers), I wouldn't have it while pregnant. I'm an anxious pregnant person and would drive myself mad wondering about side effects etc.
I would while breastfeeding, however.
If I had to go to work every day in a general-public-facing role, I think the calculation would probably come down differently, and if the NHS advised it was safe for pregnant women I probably would. If I had to go to work in an office... not sure. Depends on how covid secure I felt it really was.
But if the NHS recommends against it for pregnant/breastfeeding mothers, I'd follow that guidance and not have it.