Is the wording used to renew a void marriage contract—which is "I want to take back my wife whom I divorced"—sufficient and does it validate the contract?

The issue can be summarized as follows: The marriage of a pregnant woman due to adultery is a matter of scholarly disagreement. The Maliki and Hanbali schools, along with Abu Yusuf from the Hanafi school, hold that her marriage is impermissible before childbirth. In contrast, the Shafi'i and Hanafi schools deem her marriage permissible, as the water of fornication is not sacred. If someone other than the fornicator marries her, the Hanafi school states that it is impermissible for him to have intercourse with her until she gives birth, while the Shafi'i school permits it. However, if the fornicator marries her, intercourse is permissible, and the child is not attributed to him.

Therefore, the first marriage contract, which occurred during the pregnancy resulting from adultery, is valid according to the Hanafi and Shafi'i schools. As for the second contract, if it was concluded with an offer from the guardian and your acceptance, then it is valid, and your statement "I want to take back my wife" does not harm it. However, if what happened was merely your statement "I have taken back my wife," then it is not considered a valid contract.