A recent report by two Israeli researchers, Gideon Koren and Rana Cohen, in the Journal of Cannabis Research details the cases of four pregnant women with severe morning sickness (hyperemesis gravidarum).
One case describes, “In her 2nd pregnancy HG [morning sickness] started at 4 weeks with up to 70 bouts of vomiting a day necessitating repeated hospitalizations…”
All of the women found that 2-3 puffs of THC-rich marijuana (~20% THC, 1% CBD) was helpful to reduce or prevent vomiting and reverse weight loss. The effect from inhaling small amounts of marijuana would last 2-4 hours and then they’d dose again, using a total of 1-2 grams per day. It seems like the researchers didn’t recommend this to the patients, but that they settled on similar doses independently.
The babies are now up to 4 years old and there haven’t been any apparent developmental problems.
See study: The use of cannabis for Hyperemesis Gravidarum (HG)