If a man commits adultery with a woman and then they get married, does the Hadd punishment for adultery fall away from them, and is the marriage contract valid?

If adultery is proven before the ruler through confession or the testimony of four witnesses, the hadd (prescribed punishment) is not waived by marriage. However, if Allah has concealed their sin before their matter is brought forward, then they must repent and conceal themselves. Before marriage, repentance and clearing of the womb with one menstrual cycle are required. If she is pregnant from adultery, she cannot be married until she gives birth, for the Prophet, peace and blessings be upon him, said: "Avoid these abominations which Allah has forbidden. Whoever commits any of them should conceal himself with Allah's concealment and repent to Allah. For indeed, whoever exposes his misdeed to us, we will apply the Book of Allah Most High upon him." If the marriage takes place while she is pregnant from adultery, the child is not attributed to the adulterer, nor does he inherit from him.