SHAFAQNA – The Grand Ayatollah Seyyed Sadeq Rouhani answered a question about remarrying without having the knowledge of the issue of Eddah (period during which a divorced or widowed woman may not marry another man).
Question: A divorced woman, remarried with her second husband after 47 days whilst was unaware of the issue of Eddah and now she has 4 children; she has now informed her husband and her husband also did not know about the issue (of Eddah), what should they do?
The Grand Ayatollah Rouhani: When she was clean and divorced, if during the next 47 days she had two periods and then became clean, when she saw her third period, the Eddah is finished and the second marriage is correct and there is no problem. If during that time she did not have 3 periods, she must have been in Eddah and the second marriage is void (Batel), and the woman is Haram to the second husband for ever, and because they did not know, the children are born Halal (legitimate) and belong to their father and mother.
Source: PERSIAN SHAFAQNA