Date: Erev Shabbos Kodesh, Parashas Pekudei 5567
From: Rabbi Moshe Sofer
To: Rabbi Moshe Leib
A newly married bride who continued bleeding during intercourse claimed to sense blood issuing from the uterus itself. The Chasam Sofer rules stringently: if she felt pesichas pi hamakor she is a niddah on a Biblical level, and if she felt only a flow, the chazakah that blood exits only with hargashah — masked here by the sensation of intercourse — precludes leniency. He effectively confirms her status as a ro'ah machmas tashmish, offering no basis to attribute the blood solely to dam besulim.
Source: Shu"t Chasam Sofer YD §146