Oh god I have so many.
From the girl who was replacing me at work: "you do know that when the baby comes out, it can rip open your vagina?" But she's also the idiot who told me I was too young to have bought a house, be married and having a baby at 23. Perhaps it was coming from a place of jealously because she was older than me, single and living with her parents.
From mum: "don't lift your arms above your head! You'll strangle the baby!"
From dad: "'they' say that you should let a baby cry a little bit more each day, that way they learn you're not going to drop everything whenever they cry." I responded with "well 'they' are giving outdated and dangerous advice. Too much crying releases stress hormones which can cause irreversible brain damage. Plus, why wouldn't I respond to my crying newborn?" That shut him up quickly lol.
From MIL - basically everything that comes out of her mouth ;-)