From: Rabbi Moshe Sofer
To: Rabbi Tzvi Hersh
The Chasam Sofer defends the Rema's ruling (based on Binyamin Ze'ev) that oaths are not administered to a pregnant woman until after birth, against the Tumim's sharp criticism. He grounds the delay in the spiritual danger to the woman herself from oath-taking — drawing an analogy to the custom of deferring oaths during Tishrei — and distinguishes this from the danger to the child from a false oath, demonstrating that the Rashi–Tosfos dispute regarding Sotah is irrelevant to monetary oaths.
Source: Shu"t Chasam Sofer CM §77