Changing PTO for Maternity Leave
PTO for Maternity Leave is given twice (assuming the Sim has a job), once on discovery of the pregnancy (in game terms when the Sim "pops" into their second trimester aka show-half) and once on the birth of the child(ren).
The first value is in BHAV "Interaction - Show Half" on line 0x9 "Expression (My PTO += Literal 0x00C8)" (UC/M&G version). The value 0x00C8 (or 200 decimal) is 100 times the duration in days of the second and third trimesters.
So if your trimesters are 72 hours long (3 days), you would need to set this value to 600.
The second value is in BHAV "Interaction - Home Birth" on line 0x11 "Expression (My PTO += Literal 0x00C8)" (UC/M&G version). The value 0x012C (or 300 decimal) is 100 times the number of days to give as maternity leave.
So if you wanted to give 9 days, you would need to set this value to 900.
While it would be possible to make a mod to do this, it will conflict with every other pregancy controller out there, so it's simpler for people to just edit their own values.
Note: If you are using a custom pregnancy controller (including InTeen), the line numbers above will almost certainly be different, but the values should be in the same BHAVs.
Hope these notes are of use to someone. Enjoy!