Would You Ever Prescribe THC Or Cannabis To A Patient

Would you ever prescribe THC or cannabis to a patient who is pregnant and has severe nausea and vomiting (like with hyperemesis gravidarum)? I realize that there is not a lot of studies about the effects of cannabis on pregnancy, but from my understanding, there are no known negative side effects. Wouldn't that technically make it a Class B drug as far as pregnancy is concerned?