Making Talaq dependent on the wife's pregnancy

Q: My wife bore me three children. After giving birth to the third child and weaning him, I asked her not to get pregnant again. I said, "if you get pregnant, you will be divorced." However, I have just found out that she is pregnant even though I have used to take care while having intercourse with her so that she will not get pregnant. I hope Your Eminence will tell me whether Talaq (divorce pronounced by a husband) has been effective or not. May Allah grant you success and guide you to the good, for He is All-Hearer and Responsive.

A: You are sinful for preventing your wife from getting pregnant. Moreover, you have broken the oath of Talaq which you have made dependant on your wife's pregnancy and, thus, Talaq has been effective. You can take her back in marriage before delivery unless this Talaq is the third one. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.