After some testing, it seems to me, that adding slave modifications or hormones (maybe anything changing a slave)
using rules freezes pregnancies.
I made a game where i changed only one thing each time and then waited for the pregnancies to progress
and everything worked fine (multiple pregnancies still do not work perfect, but that is another problem)
until i made a rule, that gave each girl a Reward Center Stimulator.
After that, no pregnancy was progressing anymore.
Giving the Stimulator (or any other mod or hormone) manually to a pregnant girl or to a girl not pregnant and impregnating her later did not trigger this bug.
The same happens with the Anal and Dental Lubrication Implants and different hormones
(tested with gluteus and lactation),
also the bug happens, when you use the "apply to all" option, i asume it is the same mechanic, that rules use.
so the reason seems to be the way rules work.
Only girls that are affected by the rule have their pregnancies frozen.
Removing the rule and the mods or hormones applied by this rule do not solve the issue.
The whole rules system seems to be a bit bugy at the moment.
If i set a rule for slaves at school, that should move every slave with 100 Intelligence to a different job, nothing happens.
The same is the case for Speed training and 100 Agility.
I attach my save from my test game with several girls in different stages of pregnancies, no rules set up
and all station modules in the slave quarters are built.
The save also has a stockholm event, which is bugy at the moment, at least later in the game, when a lot of characters are active in the station it ends like this, with no way out of that screen.
I can't attach a .gal file here so i put both (.sav and .gal) into the zip.
I think i'll wait for a fix for the problem, because playing without rules is unpleasant if you have hundreds of slaves.
Also not a bug but a performance issue:
Having a station like this
is far better for game performance that having a station like this
where every hotel room and citizen appartment has the door on a walkway and everything is accessible by walking.
The AI characters tend to walk around like crazy in that case and make the game slow.
A bit sad, i like building my station i a more realistic style.