Please note that if artificial means of birth control can be used to prevent birth defects caused by the Zika virus, then it can be used for other causes of birth defects. The principle behind Bergoglio's comments make the use of artificial birth control something that can always be used--as long as the purpose intended by the users is to prevent birth defects rather than to prevent pregnancy.
It will not be long before this is taught in Conciliar settings everywhere--especially in pre-Cana classes.