What is the required Iddah for a woman whose marriage to an adult was terminated by divorce after consummation, if she gives birth less than six months after the marriage?

Primary text

If the separation occurred during the life of the husband after consummation, such as a wife of an adult who was subsequently divorced, and she gives birth less than six months from the marriage date, she must observe an Iddah of three complete menstrual cycles (Quru') after delivery.