All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Wudhoo’ (ablution) is only required for Salah [prayer], Tawaaf [circumambulation around the Ka‘bah], touching the Mus-haf [copy of the Quran], or other reasons requiring Tahaarah [ritual purity]. It is also possible that a person performs Wudhoo’ for no reason but to remain upon Tahaarah.
It is not obligatory that a woman performs Wudhoo’ in order to nurse her child. Rather, she should not do this because there is no Sharee'ah-based evidence regarding it.
For more benefit, please refer to Fatwa 173973.
Allaah Knows best.