Pregnancy story, how to divide it up?

So, I’ve been writing this story about a single woman who happens to be pregnant. It begins with the woman being forced into “personal stuff” with a “friend” of hers. I don’t go any further than that and mentioning the breakup as I am not one to go into porn type stuff and never will be, plus whenever I write a story that isn’t children’s, I write it with the assumption that all ages from teenagers to elderly would read it.

So far, I have 3 major characters in that story, one being my main character.

Emily - The woman that the story is about, the one who became pregnant and is both excited and scared at the same time

Amanda - Emily’s mom, a very caring mom helping her through the pain that is her pregnancy, and calling the doctor to make her appointments

Elizabeth - Emily’s best friend, also very caring about her.

And so far I have these chapters:
Chapter number - What it’s about
Chapter 1 - The start of her pregnancy, starting with the grim situation of her breakup.
Chapter 2 - Emily realizes she’s pregnant when she starts feeling odd and like she’s growing, she would be 1 month pregnant in this chapter.
Chapter 3 - Emily goes to have her first ultrasound only to realize that she is anemic, she thought her dizziness and hunger were solely from being pregnant, but it turns out she’s deficient in iron, 2 months pregnant.

Given that these chapters have so far been neatly divided by months, should I continue with that scheme? Or what should I do as far as dividing up the story into chapters?