The -40 physics penalty for being pregnant is permanent and cumulative. Slaves can easily get below -100 physics with penalties, leading to negative amounts of resource collection. The speed penalty also appears to be permanent.

What version are you on? Do you have a save?

No console message for either getting pregnant or giving birth. Oddly enough, both characters that gave birth regained the +40 physics, but they still retain their penalties from previous pregnancies. No never-pregnant character has any physics penalties.

The game was started in this version.

Things that might have happened :

Character not home while giving birth.

Character traveling while giving birth.

Character received death blow while pregnant.

Character on assignment while giving birth.