He replied:
If the husband accepts her statement that she married before her third menstrual period, the marriage is invalid. He must separate from her, and she must complete the waiting period from her first husband, then observe a waiting period on account of intercourse with the second husband. If she had experienced her third menstrual period before the second husband had intercourse with her, her waiting period from the first husband had ended. When the second husband separates from her, she must observe a waiting period of three menstrual periods on his account. She may then marry whomever she wishes under a new marriage contract. His child is legitimate and legally recognized as his offspring, even if born of intercourse under an invalid marriage contract whose invalidity was unknown.
He—may Allah have mercy on him—was asked:
A divorced woman claimed and swore that she had completed her waiting period, so a second husband married her. Then another woman came forward and alleged that she had experienced only two menstrual periods, and the husband believed her. What is the ruling?
He replied:
If she had experienced only two menstrual periods, the second marriage is invalid by agreement of the imams. If the husband believes this woman's statement, the couple must be separated. The wife must complete her waiting period from the first husband with one further menstrual period, then observe a full waiting period on account of intercourse with the second husband. After that, if the second husband wishes to marry her, he may do so.
He was asked:
What is the ruling concerning a woman who was irrevocably divorced and then married a month and a half later, having experienced only one menstrual period?
He replied:
She must separate from this second husband and complete her waiting period from the first husband with two further menstrual periods. After that, she must observe a waiting period of three menstrual periods on account of intercourse with the second husband. He may then marry her under a new marriage contract.