Musannaf Ibn Abi Shaybah

Hazrat Hasan (may Allah be pleased with him) says that when a man passes away or he divorces his pregnant wife, and the woman gives birth to a child while there is another child still in her womb, then the waiting period (iddah) is completed with the birth of the first child.

Ibrahim (may Allah have mercy on him) said that when she gave birth to a child, she became irrevocably divorced.

Hazrat Qatadah (may Allah be pleased with him) says that when she gave birth to a child, she became irrevocably divorced. He was asked whether she could now marry. He replied, no. Hazrat Qatadah says that there was a dispute with the servant (Hazrat Ikrimah).