Musannaf Ibn Abi Shaybah

Hazrat Ibn Sirin (may Allah have mercy on him) was of the opinion that every pregnant woman is entitled to maintenance. He gave the opinion of maintenance for the Umm Walad of Ya'la (may Allah be pleased with him) bin Khalid, but he considered it undesirable that maintenance be given to an Umm Walad without the decision of a judge. When he sent a message to Abdul Malik bin Ya'la (may Allah be pleased with him), he forbade maintenance. Hasan used to say that she will be provided for; if she gives birth to a living child, then her maintenance will be from the child's share, and if she gives birth to a stillborn child, then it will be considered void.

Hazrat Mak'hool (may Allah have mercy on him) says that if the master of an umm walad passes away, then her maintenance will be from the share of what she carries in her womb.