do not worry about your pot smoking history prior to conception...it will not make you baby come out green!

smoking tobacco or pot is not good for a developing fetus...the immediate negative effect of smoking is to starve your blood of oxygen (because of the carbon monoxide) which can result in low birth weights and premature birth...PLUS it can't be too good for your body and fetus to be putting tars and other combustion by-products in your lungs/blood...smoke contains carcinogenic compounds which may or may not be present in high enough concentrations to cause cancer

HOWEVER studies done on pot smoking pregnant women have shown that their habits have not had a negative impact on their children physically or psychologically other than a slightly lower birth weight

some pregnant people treat their body like a temple and won't take caffeine, cola, chocolate, preservatives, hydrogentated fats, chemical additives...wow...what do they eat?? a moderate approach should be adequate to protect the health of your unborn child...if you are committed to getting high then you could avoid smoking by eating your pot instead

a while ago, someone raised the issue of consent...they said that getting stoned while pregnant gets the fetus stoned too and that was unethical because the fetus cannot give its consent to ingest mind altering substances...i don't know about the ethics involved but you would definitely be sharing your buds with the little guy living in your belly...personally, i think that argument could be extended to car exhaust, perfume, food additives, pesticides, herbicides, household cleaners, electromagnetic fields and a wide range of harmful domestic products...it would be impossible to avoid exposing a fetus to potential harm from these sources but it makes sense to try to reduce the harm these things can cause

bottom line: THC (the active ingredient in MJ that gets you high) does not pose a health risk to human beings...it does not make you insane...it won't lead you to a life of crime.