Booster shot can wait till you give birth and if you have not completed all the 3 jabs required from Government in order to be fully vaccinated. Alternatively, you can choose to take it now. However, during pregnancy they will also suggest 2 vaccines for pregnant mummies. Which these vaccines and whatever vaccines we take outside of doctor prescriptions are to be atleast 6 months apart at most. You can discuss with your gynae/doctor and if they give you green light. This is what I ask with doctor during check up and she recommended to postpone till I give birth. But, then again it is your choice. Because kids will also take vaccines thats compulsory and optional. So you may decide whats the better options.