Musannaf Ibn Abi Shayba 26:73

Ibn Mahdi narrated to us, from Hammad ibn Salamah, from Abdullah ibn Muhammad ibn Aqil, who said: A daughter of al-Hasan ibn al-Hasan died, and she left behind her husband, her mother, her siblings from her mother, and her siblings from her father and mother. They went up to Umar ibn Abd al-Aziz, and he gave the husband one-half, the mother one-sixth, and he made the siblings from the mother and the siblings from the father and mother share [the remainder]. And he said to the husband: "Refrain from [distributing] your peers' shares, until you wait to see if she is pregnant or not."