Taking marijuana for the treatment of nausea and vomiting in pregnancy may cause brain problems in newborns as well as worsen the mother’s health, according to a study on 15 April.

About 70 per cent of pregnancies experience morning sickness in pregnancy, known medically as hyperemesis gravidarum, and characterised by nausea and vomiting. In severe cases, it can prevent pregnant women from eating and drinking properly, leading to weight loss and dehydration.

However, resorting to cannabis may be harmful to the health of both the mother and child, according to a review of studies published in CMAJ (Canadian Medical Association Journal).

“Use of cannabis in pregnancy has been associated with adverse neurocognitive outcomes in offspring, as well as other adverse pregnancy outcomes. Therefore, we advise against the use of cannabis in pregnancy,” said Dr Larissa Jansen, Amsterdam Reproduction and Development Research Institute, Erasmus MC, Netherlands.

To date, the cause of morning sickness is not completely understood. Yet pregnancy at a young age, a female foetus, multiple or molar pregnancies, underlying medical conditions, and a history of the condition during previous pregnancies are some known risk factors.

“Hyperemesis gravidarum can have detrimental effects on maternal quality of life and may lead to short and long-term adverse outcomes among offspring,” said Dr Larissa.

“Management of hyperemesis gravidarum requires considerable healthcare resources, as it is a common reason for hospital admission and emergency department visits in the first trimester,” she added.

Anti-nausea drugs and home remedies such as ginger products may help alleviate mild nausea and vomiting for some people, but the evidence of its effectiveness in people with hyperemesis gravidarum is uncertain, the team said, calling for more research.