Tanja is one of the nine contestants left on the show. She was seven months pregnant when she entered the house in August.
She gave birth in a special room of the house, according to strict ground rules set by the Dutch Social Affairs Ministry. The child will stay in an area where cameras are not allowed. Her mother and relatives can visit her privately.
The birth was recorded and broadcasted 8 hours afterwards, by agreement between the show's producers and the authorities.
The reactions at the event varied. The contestants are supporting Tanja and are "very proud" of her. But some of the audience is outraged, accusing Talpa, the TV station that broadcasts the show, of exploiting the birth to boost its ratings.
Spokeswoman Stephanie Dekker answered that far more explicit scenes were shown on TV in medical or educational programs.
Tanja is healthy and hopes the birth will increase her chances to win the contest, with a prize of 400,000 euro.
Big Brother was created in the Netherlands six years ago and has since been marketed in dozens of countries throughout the world.