Hmm. My hair didn't go straight, it got curlier in places, like a few curls around the front and the nape. I'm 3b normally but those areas were 3c. Second day hair was a disaster because the nape was so tangled I couldn't even pull it up. But hair was the tip of the iceburg. The prolactin from breastfeeding gave me a severe migraine every 24 hours, so I had to quit.
I'm at 3.5 months post partum, and I've also shed quite a bit, especially at the hairline, which freaked me out. I have to wear my hair down the entire time so you can't see the spots, but it's slowly growing back.
Hormones are weird, aren't they?