Does the Sharia allow you to perform Mutah in a situation when your wife isn't able to have intimacy with you due to a high risk pregnancy and the period of such lack of intimacy exceeds 9 months?
Mut'ah marriage is a way to save people from falling into sinful acts but such type of marriage has conditions which must be fulfilled. If you need to save yourself from falling into sinful act through going for Mut'ah marriage, you need to get your Muslim wife's permission if you want to do the Mut'ah with a woman from People of Book (Ahlul Kitab) like Christians or Jews.
Wassalam.