The breastfeeding that renders marriage unlawful is five or more times during the first two years. If your wife breastfed the girl in this manner, she will be your foster daughter and the foster sister of all your children, even if she drank the milk through the bottle. Allah (Exalted be He) states:
Forbidden to you (for marriage) are: your mothers, your daughters
...your foster milk suckling sisters
Allah (Exalted be He) also says:
The mothers shall give suck to their children for two whole years
Further, it is confirmed that the Prophet (peace be upon him) stated:
"Milk-relations (Part No. 21; Page No. 15) forbid what blood relations do."
It is related on the authority of
`Aishah (may Allah be pleased with her) that she said: "It was among the revelation of the Qur'an that ten known times of breastfeeding make the marriage prohibited, but this was later abrogated and reduced to five. The Messenger of Allah (peace be upon him) died and the ruling remained effective." One time of breastfeeding is when the child holds the breast and sucks milk. If the child leaves the breast and then holds it again to suck milk, this will be a second time.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.