Aric never changed abortions to support his mod, so any attempt to abort a baby will result in a reset pregnancy timer and an error rather than removing the baby. So as long as you keep trying to abort the baby, it will never be born and she will stay pregnant.
The easiest way to fix this is to open person.gd (.../STRIVE_PROGRAM_FOLDER/files/scripts/person/person.gd) and change the contents (the 5 lines after header) of "func abortion():" to:
while !preg.unborn_baby.empty(): globals.miscarriage(self)
Be sure to make a backup of the file first and use a decent text editor. Each line should have leading tabs instead of leading spaces(1 tab instead of 4 spaces) so you will need to change that if you copy and paste this code.