What’s that movie?

So I will never forget a face but I’m really bad with names, including actresses and apparently movies. I keep thinking about this movie, please help me remember the name so I can watch it:) lol.

Plot: So this lady gets pregnant around the same time as her close-to-her-age stepmom (?) stepmom I think was pregnant with twins and had a perfect no symptom pregnancy and she just had all the worst symptoms throughout hers. I think she was an author (in the movie).

Lol. Anyone?