social security - arriving to Belgium pregnant (Brussels)

Hi all. Happy new year!

My wife and I are arriving in Brux this week from the UK. I'll be working as a contractor and my wife will stay at home as she is pregnant. She needs to sign up for doctors and checkups asap. My question is: is my wife covered by any social security if she's not working? What needs to be done so she can be attended as local?

Appreciate your advice,
Radek