Is the fatwa you mentioned, concerning the obligation to refrain from marital relations for three months after the marriage contract due to the engaged couple having had sexual intercourse before the contract, Islamically sound? And what is the Sharia ruling on what they did?

If an engaged woman commits adultery before the marriage contract (aqd), she has committed the crime of zina (fornication/adultery). Both she and the man with whom she committed zina must repent before the aqd. Scholars have differed regarding the necessity of istibra’ al-rahm (clearing of the womb), and the most preponderant opinion is that it is one menstrual cycle.

As for marrying an adulteress (zaniyah), Ibn Taymiyyah stated that it is forbidden until she repents, whether the man who committed zina with her was he or someone else. This is the madhhab (school of thought) of Ahmad ibn Hanbal. However, many of the Salaf (early Muslims) permitted it, with Malik stipulating istibra’, and Abu Hanifah permitting it before istibra’ if she is not pregnant. Al-Shafi'i permits the marriage contract and intercourse absolutely. The correct view is that istibra’ is obligatory. It is incumbent upon anyone who has given a fatwa without knowledge to clarify the correct ruling and warn against issuing fatwas without knowledge.