Does the repeated statement "I am not a Muslim, I am a Christian" expel a Muslim woman from the faith, even if said in a fit of anger? And does she need to re-recite the Shahada and renew the marriage contract?

If a Muslim states that they are not Muslim, or that they are Christian or Jewish, this statement constitutes apostasy from Islam, unless there is an impediment to declaring them a disbeliever, such as ignorance, compulsion, or a mind overwhelmed by extreme joy or anger. In such cases, they are not deemed a disbeliever. However, if they say this by choice and intent, or if their anger did not overpower their intellect, then it is disbelief and apostasy. Whoever falls into this must utter the two testimonies of faith (Shahadatayn) and disavow every religion that contradicts Islam in order to return to it. If the wife apostatizes before consummation, the marriage is immediately annulled. If it occurs after consummation, it depends on the completion of the waiting period ('iddah); if she returns to Islam within it, they remain married, otherwise the marriage is annulled.