Yahya bin Sa'id (may Allah have mercy on him) said that Sayyiduna Zayd bin Thabit (may Allah be pleased with him) was asked whether a man who, after marrying, divorces his wife before having intercourse with her may marry her mother. Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: No; she is her mother, there is no doubt about this, and there is no condition attached to it; the condition is only regarding the (wife's) daughters.
(b) Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: If she dies, marriage to her mother is not permissible; and if he divorces her, then he may marry (her mother) if he wishes.
This report is munqati' (its chain is broken).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13907