A recent study published in American Journal of Obstetrics and Gynecology review cannabis use on reproductive health, pregnancy and fetal outcomes.
Cannabis, a federal illicit drug, is the most widely used drug in the United States. Its consumption is increasing worldwide, partly due to legalization in several regions and growing social acceptability and accessibility. Cannabis use is increasing, especially among people of reproductive age. Increased cannabis consumption during the 2019 coronavirus disease pandemic (COVID-19) may be due in part to increased stress and anxiety.
The endocannabinoid system mediates the biological effects of cannabis. Endocannabinoid receptor expression was observed in developing fetuses during the fifth week of gestation. Cannabinoid receptors in the male / female reproductive tract, sperm and placenta have been reported, indicating that the endocannabinoid system may regulate reproduction. Delta-9-tetrahydrocannabinol (THC), the main psychoactive element of cannabis, is found in breast milk and can cross the placenta.
In addition, evidence of the safety of cannabis use, especially with regard to reproductive health and pregnancy, is limited. As such, nearly 70% of women in the United States believe that cannabis consumption once or twice a week is harmless. Given the increase in cannabis consumption, it is necessary to study the effects / effects of cannabis on reproductive health and the results of offspring development.
Cannabis is a member of the Cannabaceae family and has over 80 bioactive chemicals, with THC and cannabidiol being the best known. Cannabinoid receptors (CB1 and CB2) are expressed in the central nervous system and peripheral tissues. Some of the therapeutic properties of cannabinoids include muscle relaxation, analgesia, anti-inflammatory action, immunosuppression, sedation, mood enhancement, anti-emesis and appetite stimulation, among others. However, cannabinoids are not approved for therapeutic use.
Consumption and legalization of cannabis
Smoking is the most common way to use cannabis, followed by edible products. Cannabis Disorder (CUD) occurs in about 10% of regular users and 50% of chronic users. Therapeutic options for CUD are limited and include psychosocial intervention, motivation therapy, and cognitive-behavioral therapy or a combination. Several American, African, European and Australian regions have decriminalized cannabis use.
Significantly increased cannabis consumption is due to the legalization of cannabis for entertainment. In the United States, 18 states have legalized cannabis for entertainment in 2021. These legal changes are likely to affect cannabis use among adolescents and children. It has been suggested that puberty and the mental health of the pediatric population may be affected by cannabis use.
Cannabis use by men and paternal influence
The effect of chronic cannabis consumption among men is inconsistent, with minimal or no changes in follicle-stimulating hormone (FSH) levels or worsening sperm parameters. Animal studies have shown that exposure to THC can lead to adverse effects on spermatogenesis, decreased gonadotropins, abnormal sperm morphology and testicular atrophy.
A recent report showed that cannabis exposure in rats and humans was associated with altered methylation of deoxyribonucleic acid (DNA). Affected genes are involved in cancer and early development, including neurodevelopment.
Effects of cannabis on women’s reproductive health, pregnancy, lactation and fetal outcomes
Various studies have shown that cannabis affects processes related to women’s reproductive health, such as ovulation, secretion of luteinizing hormone (LH) and FSH, and the menstrual cycle. Studies in mice have shown that prolactin, FSH and LH levels are suppressed by acute administration of THC. Women who use cannabis during pregnancy are often involved in the use of polysubstants, which leads to a synergistic or additive effect.
In addition, half of women who use cannabis continue to use it throughout pregnancy. There are growing concerns about adverse fetal / neonatal outcomes, as THC may bind to cannabinoid receptors in the placenta or fetal brain. The risk of miscarriage and stillbirth is also higher, but is inconsistent in different studies. Some studies suggest higher chances of admission to the neonatal intensive care unit (NICU), low gestational age (SGA), placental abruption and infant death.
Impaired cytotrophoblast fusion and biochemical differentiation by THC have been observed in vitro. In addition, THC inhibits the migration of the amniotic epithelial layer, affecting its development during gestation and contributing to adverse pregnancy outcomes, including premature birth. Hyperactivity, impulsivity, unusual visual and verbal reasoning, and attention deficit have been reported in preschool children born to mothers who used THC during pregnancy.
Breastfeeding mothers are likely to increase cannabis use within two months of giving birth. This raises concerns about the gradual release of THC from lipid-filled tissues in the offspring transmitted through breast milk. In addition, chronic cannabis use increases THC levels more than eight times in breast milk compared to plasma. Newborns with THC exposure within one month after birth were observed with reduced motor development.
As cannabis use increases, data on its safety, especially for reproductive health, are limited. The current literature suggests that its use has significant health consequences and it is a serious concern that 70% of women believe that its use is safe during pregnancy. It should be noted that only half of health care providers discourage perinatal cannabis use.
Despite limited safety information, it is crucial that both individuals and healthcare providers be informed of the potential adverse effects of cannabis, especially before conception, during pregnancy and during the postpartum period.