From: Rabbi Moshe Sofer
To: Rabbi Simcha Bunim Ginz (Eiger)
A postpartum woman who saw blood three times during relations sought treatment from non-Jewish physicians. The Chasam Sofer rules that reliance on non-Jewish physicians' prescriptions alone is insufficient, but validates the moch-without-shfoferes examination endorsed by the Emunas Shmuel and others, refuting objections raised by the Noda BiYehudah and others. He permits combining multiple lenient factors — including the nursing-mother leniency, attribution of blood to a wound, the role of pain, and physicians' testimony as a contributing consideration — deferring the final practical ruling to his mechutan.
Source: Shu"t Chasam Sofer YD §158