What is the ruling regarding a woman who, in a state of anger with her husband, vowed not to get pregnant, and linked the opposite (i.e., getting pregnant) to fasting 60 days?

A woman's vow never to conceive due to a quarrel with her husband is a forbidden vow. It is impermissible to fulfill it because it contradicts the Prophet's (peace be upon him) command to procreate and violates his prohibition against vows of disobedience. What she has made contingent on this vow falls under the category of a vow of obstinacy (nadhir al-lajaj).