It was narrated that 'Aishah said: The Messenger of Allah (ﷺ) swore that he would not enter upon his wives for a month, and he stayed for twenty-nine days until, on the eve of the thirtieth, he entered upon me. I said: 'You swore not to enter upon us for a month.' He said: 'The month may be like this,' and he held up his (ten) fingers three times; 'or the month may be like this,' and he held up his fingers three times, keeping one finger down on the third time.
It was narrated from Aishah that: the Messenger of Allah (ﷺ) swore to keep away from his wives, because Zainab had sent back her gift and 'Aishah said: She has disgraced you. He became angry and swore to keep away from them.
It was narrated from Umm Salamah that: the Messenger of Allah (ﷺ) swore to keep away from some of his wives for a month. On the twenty-ninth day, in the evening or the morning, it was said: O Messenger of Allah, only twenty-nine days have passed. He said: The month is twenty-nine days.