What is the ruling on marital intimacy during the engagement period, which resulted in a pregnancy and the birth of a daughter? Does this entail sin or expiation, knowing that they subsequently married and had two more children, and are now living a peaceful life?

If intercourse occurs between the fiancé and fiancée after the legal marriage contract but before the wedding, there is no sin upon them. However, if intercourse occurs before the contract, it is considered zina (fornication/adultery). The expiation for zina is sincere repentance that fulfills its conditions: ceasing the sin, regretting it, and resolving not to return to it, along with concealment and not publicizing it. Scholars have differed regarding the ruling on the zani (fornicator/adulterer) marrying the woman who became pregnant by him through zina. The majority of them hold that it is not permissible for him to marry her until she has repented and delivered her child, while some consider the marriage valid and the child attributed to him.