Does pregnancy change a person hormonally/chemically?

I can remember that before my wife got pregnant she could put on muscle through exercise almost easier than me, I used to joke that she should stop before she looked like a female body builder. After pregnancy? Yeah her previous toned look melted away into flab(not that I complained) and she can’t build muscle now to save her life.

Also a sort of TMI issue is that when she is ovulating she has a vaginal discharge not unlike plain jello, which disturbed her the first time it happened. I remember her yelling for me to come and then she was like WTF is this? I was like I don’t know, she swears it never happened before her pregnancy and it seems to be cervical mucus through online searches.

Is there any science on this? Does a pregnancy really change a woman permanently?

The women I know say yes. I say yes too. And it is quite odd and unpredictable, often. For example I was plagued for years with chronic bladder infections, before I got pregnant. Never had one again.