So sorry that this is so old, but I appear to be having the same problem. This is the first script mod I've installed, I've followed all of the instructions that came with the download page (found here:
http://modthesims.info/download.php?t=547232), and script mods are enabled in my game. I haven't unzipped the _script file, I've done nothing with the package file either. I've put both into my mods folder, under The Sims 4.
I use Windows 10 Anniversary Edition, I bought my game late September.
I am 100% sure I'm using it on a pregnant sim too, she's in her first trimester according to the game.
What do!?