Musannaf Ibn Abi Shaybah

Hazrat Ibn Abbas (may Allah be pleased with them) narrates that a woman experiencing istihada will delay the Zuhr prayer and offer the Asr prayer early, and she will combine the two, performing one ghusl for both. She will delay the Maghrib prayer and offer the Isha prayer early, and she will combine the two, performing one ghusl for both, and then she will perform ghusl for the Fajr prayer.

Hazrat Ikrimah says that a woman experiencing istihada will combine two prayers.

Hazrat Qasim says that a woman experiencing istihada may, if she wishes, combine both prayers.