I went to a gym 3 nights a week before I got pregnant; due to my high-risk factor, I had to give that up immediately upon learning I was pregnant.
Less than 3 months after giving birth, I resumed the gym. Big mistake. I was still loose-jointed, hurt myself twice there and finally gave it up for good when I fell down my own stairs, twisting my foot and ankle.
My neighbor, also the mother of twins, went back to work within two weeks to a job that required her to be on her feet the entire shift. Less than 10 years later, she had a hysterectomy-doing what she did caused uterine prolapse because she didn't give herself time to rest and heal.
It's all in what the body is used to. My sister is a dancer and danced into her 9th month with both kids. Wanna see something really weird, imagine a full term woman sitting on a floor doing a complete split. She looked like Humpty Dumpty