It is narrated from Sayyidah Umm al-Fadl (may Allah be pleased with her) that the Prophet of Allah (peace and blessings be upon him) said: "Being breastfed once or twice, or sucking once or twice, does not establish the prohibition (of marriage)."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21494