Is the marriage valid if the wife was pregnant before the marriage, and what if the wife denied her previous pregnancy, and is she required to swear an oath, and what is the fate of the child and his lineage?

The validity of the marriage in this case can be summarized based on the time of the marriage contract and the time of pregnancy. If the contract was concluded before the possibility of pregnancy, then it is valid. However, if her pregnancy was confirmed before the contract, then the marriage is invalid. Pregnancy is confirmed by her confession or by the testimony of two reliable doctors along with the presence of signs of pregnancy.

The default is that the child is attributed to the husband unless the husband denies him through li'an (oath of condemnation). If the husband is certain or strongly believes that the child is not his, either through the testimony of doctors or by the child being born less than six months after consummation, then he must deny him through li'an. However, if the woman gives birth between six months and four years [from consummation] and she did not observe istibra' (purification period) with a menstrual cycle, then denial is forbidden.

If li'an occurs, an eternal separation takes place between the spouses, the child's lineage is denied from the husband and attributed to his mother, and the mother is responsible for his maintenance.