R. Ovadia Yosef on Whether a Pregnant Woman's Conversion Works for Her Fetus (18 Adar Sheni)

שו"ת יביע אומר יורה דעה ט:יז 18 Adar Sheni 5730 (1970)

A woman converted to Judaism without telling the court that she was pregnant. Can her conversion count for the baby, or does that baby need to be converted after birth? In general, how does halacha think of/treat a fetus and its relationship to the mother?