# Cannabis in pregnancy

Cannabis consumption in pregnancy is an important public health issue. Research has found possible or likely associations between cannabis use and a risk of adverse outcomes in respect of cognitive development, mental health, physical health, and lactation.
Cannabis is the most commonly used controlled substance among pregnant women.

## Endocannabinoid system

The role of the endocannabinoid system (ECS) in female fertility has long been suspected and studied. Most studies through 2013 linking development of the fetus and cannabis show effects of consumption during the gestational period, but abnormalities in the endocannabinoid system during the phase of placental development are also linked with problems in pregnancy. According to Sun and Dey (2012), endocannabinoid signaling plays a role in "female reproductive events, including preimplantation embryo development, oviductal embryo transport, embryo implantation, placentation, and parturition". Karusu et al (2011) said that a "clear correlation ... in the actual reproductive tissues of miscarrying versus healthy women has yet to be established. However, the adverse effects of marijuana smoke and THC on reproductive functions point to processes that are modulated by ECS.".
Recent data indicates that endometrial expression of cannabinoid receptors in marijuana smoking mothers is higher than non-smokers. Keimpema and colleagues (2011) said, "Prenatal cannabis exposure can lead to growth defects during formation of the nervous system"; "[c]annabis impacts the formation and functions of neuronal circuitries by targeting cannabinoid receptors ... By indiscriminately prolonging the "switched-on" period of cannabinoid receptors, cannabis can hijack endocannabinoid signals to evoke molecular rearrangements, leading to the erroneous wiring of neuronal networks". A report prepared for the Australian National Council on Drugs concluded cannabis and other cannabinoids are contraindicated in pregnancy as they may interact with the endocannabinoid system.

## Evidence

As of 2023 the rising use of cannabis during pregnancy, and the rise in cannabis potency, has become an important public health issue. Research has found possible or likely associations between cannabis use and a risk of adverse outcomes in respect of cognitive development, mental health, physical health, and lactation.

### Mental and cognitive

Cannabis use during pregnancy is associated with adverse effects on the mental health and cognitive performance of offspring. The THC exposure resulting from cannabis use interferes with fetal brain development and the male offspring of users are more susceptible to psychotic illness.

### Epigenetics

THC exposure in rats during the prenatal developmental phase may cause epigenetic changes in gene expression, but there is limited knowledge about the risk for psychiatric disorders because of ethical barriers to studying the developing human brain. A 2015 review found that cannabis use by pregnant mothers corresponded to impaired brain maturation in their children, and that those children were more predisposed to neurodevelopmental disorders; these results do not demonstrate causality.

### Confounding factors

The National Institute on Drug Abuse stated in 2018 that further research is required to "disentangle" effects of cannabis use from a mother's concomitant drug use and other environmental factors.

## Developmental observations

Developmental observations suggest that CB1 receptors develop only gradually during the postnatal period, which block for the psychoactive effects of cannabinoid treatment in the young organism. Therefore, it is suggested that children may respond positively to medicinal applications of cannabinoids without undesirable central effects. Clinical results have been reported in pediatric oncology and in case studies of children with severe neurological disease or brain trauma, and cystic fibrosis (CF) suggesting cannabinoid treatment for children or young adults, in order to achieve an improvement of their health condition including improved food intake and reduced inflammatory exacerbations.

## Morning sickness/hyperemesis gravidarum

Hyperemesis Gravidarum (HG), is a debilitating ailment characterized by severe nausea and vomiting, malnutrition, and weight loss during pregnancy, and occurs to 1-2% of pregnant women globally. It is a perplexing female mystery for the present-day medical establishment. The frustration is mostly felt by women who are survivors of HG, desperately searching for a cure and increased understanding of this disease. Several pregnant women have revealed their personal experience with cannabis, having used it to relieve symptoms of HG, who would otherwise have become severely emaciated, dehydrated, and malnourished due to persistent, uncontrollable vomiting and the inability to eat and drink in their pregnancy.

## Society and culture

It is a common misconception that cannabis use in pregnancy is low risk; a 2015 study found that 70% of women in the United States assume that using cannabis 1-2 times a week while pregnant is safe.