All Perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as that of his family and all his companions.
Interrupting an obligatory prayer intentionally without any Islamicly valid reason is forbidden according to the consensus of Muslim scholars because it reflects undermining worship which contradicts its sacredness and high status. Allaah Says (what means): {O you who have believed, obey Allaah and obey the Messenger and do not invalidate your deeds.}[Quran 47:33].
If it is a supererogatory prayer then interrupting it without any Islamicly valid reason is also forbidden just as the obligatory prayer, according to the Hanafi and Maaliki, schools of jurisprudence. Shaafi’ee and Hanbali schools of jurisprudence are of the opinion that though interrupting the prayer is allowed but it is not advisable. However, the first opinion that forbids interrupting the prayer is the preponderant one.
Muslim scholars have agreed that interrupting prayer is obligatory only to respond the call of the Prophet . It was amongst his peculiar characteristics.
It is written in encyclopedia of Islamic jurisprudence: "It was among the peculiar qualities of the Prophet that if he calls any one, he should answer him even if he is performing prayer. If he answers the call of the Prophet during his prayer his prayer will not become null, for the narration of Abu Sa'eed bin Al-Mu’alla Al-Ansaari that the Prophet called me, but I did not go to him till I had finished my prayer. When I went to him, he said: "What prevented you from coming?" I said: "I was praying." He said: "Didn't Allaah say, {O you who have believed, respond to Allaah and to the Messenger when he calls you…}[Quran 8:24].”
Therefore, a wife should not interrupt her prayer to respond to the call of her husband.