A vaccine contains tiny pieces of the germs that cause a specific disease.
These pieces are called antigens.
When you get the vaccine, your immune system detects the antigens and makes antibodies to help fight that specific disease.
If you or your baby are exposed to the disease later, these antibodies will recognise it and fight it.
When you have a vaccine during pregnancy, the antibodies in your blood cross the placenta into your baby's blood to protect your baby against the disease at birth.
By getting vaccinated, you're protecting both you and your baby from serious illness.
The influenza and pertussis vaccines are recommended for pregnant women.
Influenza and pertussis, also called whooping cough, can cause serious harm to pregnant women and their unborn babies.
The most effective way to prevent serious illness from these diseases is to get vaccinated.
Babies cannot be vaccinated against whooping cough until they are two months old and cannot be vaccinated against influenza until they are 6 months old.
By getting these vaccines during pregnancy, you can protect your baby in their first few months after birth, when they are most vulnerable but too young to be vaccinated.
The influenza and whooping cough vaccines are free for pregnant women under the National Immunisation Program.
For more information, visit health.gov.au/immunisationforpregnancy.