i stretched through the pregnancy and then i waited about a month to touch up. i had soooo much shedding and tangling, i was at the salon half the night. it took 6 or 7 hours to get my hair untangled. i was nursing too so i was in pain from top to bottom. my chest got engorged while i was there. it was such an awful experience, so then i went another 5 months or so. still traumatized i stretched for 10 months after that.
i know plenty of ladies that have no issues. some burn. my experience was so bad...my hair was thin and tangly and shedding. it was not a great time for me to relax.
the hormones are still high right after delivery so you may be sensitive. another thing to consider is that if you post partum shed, the shedding usually starts around 5 months post.
if i had to do it again, i would wait 3 months. that way my hormone levels would be a little less but i would still have some time to get a touch up before i start shedding alot.
then i wouldn't touch up again until after the post partum shedding ends.