What is the ruling on a vow that did not specify a time for the slaughter, along with the obligation to fulfill it and an expiation for an oath?

The previous fatwa, No. 83805, is clear, and its gist is that as long as pregnancy has occurred, your husband is obligated to fulfill the vow. Since he did not specify a time for fulfillment, he is not bound to fulfill it at a particular time. However, it is better for him to hasten in fulfilling it according to his ability.