It is narrated from Sayyiduna Mu'adh bin Jabal, Abu Ubaydah bin al-Jarrah, Ubadah bin al-Samit and Shaddad bin Aws (may Allah be pleased with them) that the Messenger of Allah (peace and blessings be upon him) said: "If a woman kills deliberately, she is not to be executed until she gives birth to what is in her womb, if she is pregnant, and until she appoints a guardian for her child. And if she commits adultery, she is not to be stoned until she gives birth to what is in her womb, and until she appoints a guardian for her child."
Hadith Referenceالمعجم الكبير للطبراني / باب الشين / 7107