From: Rabbi Mordechai Leib Winkler
To: Rabbi Yaakov Halberstam
The responsum addresses whether nursing women, who must expose their breasts, are subject to the laws of 'Tefach b'Isha Ervah' or the requirement for netilat yadayim before prayer and Torah study due to touching a private area.
Source: Orach Chayim II §21