And if your character ever gets pregnant, the character does get pregnant but nothing ever happens as a result. That's because the condition to advance the pregnancy time checks if $player.pregnant == true, when $player.pregnant is actually set to "yes"
so this:
<<if $player.pregnant == true>>
<<set $player.pregtime ++>>
<<set $player.pregtime ++>>
<</if>>
should be:
<<if $player.pregnant == "yes">>
<<set $player.pregtime ++>>
<<set $player.pregtime ++>>
<</if>>