There is no problem with it... there are some chances of complications. But there is a greater risk with taking caffine, prescription drugs, tobacco, or alcohol. AS long as the weed you get is 100% Organic, with no chemicals. I cant say thats its benifecial because it is yet to be publicized. But i can say from personal and peer's experiance that weed wont hurt.
I am no professional and dont claim to know everything, especially talking about such a serious matter...
This link has some real information...
Is it safe to smoke marijuana during pregnancy? | BabyCenter
In the Expert answer is says
no... However,
the govt would rather you use a anti nausea medication. and I'm sure a doctor wants you to come to him so he can make that money too... so there gonna tell you that its bad. ADHD this, Nervous System Imparment that, cancer... We didnt have those health/mental issues 100 years ago... women have been smoking weed for almost 10,000 years to deal with the hardship of labor. So i'd
listen to the people not the experts. And where are all the studies coming from? where are they getting there information? Research facilities funded by the drug companies?... There not going to let that happen otherwise everyone would grow there own medicine and the drug companies would go out of business, and in turn the govt would loose billions and there health care system as lucrative as it is for them would fail... cause no one would be sick anymore cause they wouldn't be taking all the chemicals that are pumped into our bodies every day by the air we breath and the food we eat.
100% organic is the only way to go when you are pregnant.
And the sick thing is its all about control and wealth.
Look that "The Community answers:" Within the link I have provided above... that will answer you're question if i have not already...