Is it permissible for my wife to perform tayammum and pray while sitting or lying on the bed during the two weeks following an IVF procedure, in order to provide the conditions for the success of the procedure?

The IVF procedure is Islamically permissible when needed, provided that the sperm and ovum are from the married couple and the embryo is implanted in the wife's womb, or by injecting the husband's sperm into the wife's womb. As for tayammum (dry ablution) and abandoning standing in prayer for a woman undergoing this procedure, it is permissible if trustworthy doctors determine that wudu' (ablution) and standing would adversely affect her. Tayammum is prescribed when one is unable to use water, and sitting is prescribed when one is unable to stand, with emphasis on actual inability. If she is able to perform wudu' while sitting or with assistance, it becomes obligatory for her. Likewise, if she is able to stand, due to the Prophet's (peace be upon him) saying: "Pray standing; if you are unable, then sitting; and if you are unable, then on your side" (narrated by Al-Bukhari). If she is unable to pray on her side, then she may pray lying down with her feet facing the Qiblah and her head slightly raised.