Pregnancy remains possible while smoking cannabis, as cannabis use does not act as a form of contraception. The primary psychoactive compound, delta-9-tetrahydrocannabinol (THC), interacts with the body’s natural systems. This interaction can affect the reproductive processes in both males and females.
Impact on Female Conception and Hormones
THC affects the female reproductive system primarily by disrupting the hormonal balance that governs the menstrual cycle. The body’s endocannabinoid system (ECS), which regulates processes like hormone release, is influenced by external cannabinoids. This interference can slow down the release of gonadotropin-releasing hormone (GnRH) in the brain.
The reduction in GnRH diminishes the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. These hormones trigger egg maturation and ovulation. Disruption can lead to delayed ovulation or anovulation, where an egg is not released.
This hormonal shift can result in irregular or longer menstrual cycles, making it difficult to accurately predict the fertile window for conception. Studies suggest that women who use cannabis may take longer to conceive compared to non-users. Data indicates a lower success rate of conception within a six-month period for women who smoke cannabis daily.
THC may also interfere with the implantation of a fertilized egg into the uterine lining. The ECS plays a part in preparing the uterus for pregnancy, and THC may reduce the uterine lining’s receptivity. This can lead to early pregnancy loss or a reduced success rate in assisted reproductive technologies like in vitro fertilization (IVF). Women undergoing IVF who use cannabis may have a lower number of eggs retrieved and lower fertilization rates.
Effects on Male Fertility
Fertility is a joint process, and cannabis use can significantly impact the male contribution to conception. THC binds to cannabinoid receptors found directly on sperm cells and within the male reproductive tract. This interaction can impair several aspects of sperm health essential for fertilization.
Frequent cannabis use is associated with a decrease in the overall quality of semen, including reduced sperm concentration and total sperm count. Some studies report a nearly 30% lower sperm concentration in men who use cannabis more than once a week. THC exposure also negatively affects sperm motility, which is the ability of the sperm to swim effectively toward the egg.
The shape of the sperm, known as morphology, can be altered by cannabis use, with a higher proportion of abnormally shaped sperm observed in users. THC can disrupt the hypothalamic-pituitary-gonadal axis, which regulates testosterone production and spermatogenesis (sperm creation). These changes negatively affect the sperm’s ability to reach and fertilize an egg.
The effects on male reproductive health are often reversible after discontinuing use. Research suggests that abstaining from THC for at least four months can allow for partial restoration of semen quality, aligning with the time it takes for new sperm to mature. Men who are trying to conceive are advised to avoid cannabis use.
Fetal Risks Associated with Prenatal Exposure
Once conception has occurred, continued cannabis use introduces potential hazards to the developing fetus. THC is a highly lipid-soluble molecule, meaning it easily crosses the placental barrier, directly exposing the fetus to the compound. The fetal brain, which possesses cannabinoid receptors, is particularly vulnerable.
Prenatal cannabis exposure is consistently linked to adverse birth outcomes. These risks include a higher incidence of low birth weight and being born small for gestational age. Exposure is also associated with an increased likelihood of preterm birth and the need for admission to the Neonatal Intensive Care Unit (NICU).
The exposure can also affect the neurodevelopment of the child. Studies suggest an increased risk for neurodevelopmental disorders, including Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD). Long-term follow-up has indicated subtle cognitive deficits and problems with attention and executive function in children exposed to cannabis in the womb.
THC is secreted into breast milk due to its fat-soluble nature, where it can be detected for weeks after use because of its long half-life. Due to the known risks of THC exposure to the developing brain, major health organizations recommend the immediate cessation of cannabis use for individuals who are pregnant, trying to conceive, or breastfeeding. Consulting with a healthcare provider is recommended for anyone struggling to stop use.