Many women experience a smaller butt after they have had a baby, it becomes more flat than before.
I experienced this myself after each kid.
In my case, it has mostly to do with that I got more inactive and did not use my muscles as much during pregnancy
And therefore my muscles got smaller.
When we are pregnant,our pelvic will tilt even more when our baby is growing bigger,and when you have anterior pelvic tilt this will create a different posture than you had before.
This posture will lead to less active glute activity which will weaken the glutes even more because you are not using them properly.
Other factors can also be from hormones, or when you breast feed, your fat will be burned more from your butt and hips.
I noticed from my first pregnancy,my butt was more flat and lose,and it was harder to train my butt back.
One reason was because I was lacking motivation to train as well.
I trained for a couple of weeks or a month and then took a break,back and forth.
After about 2-3 years later I had the motivation I needed and I got my butt “back” and even more!
My second pregnancy, I had the same issue, But this time It only took me 11 months to gain my butt muscles back.
So if your butt has become smaller after your pregnancy, don’t worry, you will get it back if you start to train your glutes and eat right,and you can actually gain it even bigger if you want that!