That's definitely a question for your doctor's office. I would guess as soon as you feel up to it, but don't think many of us could possibly know the answer.
If you have a vaginal delievery I am sure you can ride a rollercoaster as soon as you want to after delivery. I know that you wouldn't want to n the first couple of days, but if the birth was uncomplicated I am sure you could ride one in a week or two. I can't imagine having the chance to so quickly though.
I would say that once you have your 6 week check up you should be able to but I will warn if you are breastfeeding you may be uncomfortable depending on the type of coaster you go on...
Re: How soon to ride rollercoasters AFTER pregnancy?