The whooping cough (aka pertussis) immunisation is recommended between 20 and 32 weeks of pregnancy (although it can be given up to the time of delivery). It is the best way to protect your baby against whooping cough.
Whooping cough is a serious disease of babies and can be deadly. When you are immunised while pregnant, your antibodies transfer from you to your developing baby. Your baby will then have some protection against whooping cough until such time they can have their first immunisations at 6 weeks of age.
Before the arrival of your baby, it is also recommended that all members of your household should be up to date with their whooping cough immunisations including:
A) School-age children,
B) Fathers, grandparents, and other adults who will be visiting and/or helping care for your baby.
We can understand that some women may be cautious about getting vaccines during pregnancy. If you and/or the other adults did not receive the whooping cough immunisation during your pregnancy, then it is important to get it as early as possible after the birth.
https://www.health.gov.au/topics/immunisation/vaccines/whooping-cough-pertussis-immunisation-service