Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.
Research suggests that marijuana can negatively affect female fertility in the following ways:
Furthermore, the effects of marijuana on fertility seem to accumulate over time. This means that although teenage girls who smoke marijuana are more likely to get pregnant, by the time a chronic marijuana smoking woman is in her mid-twenties, she may be more likely to experience a delay in getting pregnant.
Despite the relaxation effects that many people associate with marijuana use, research has shown marijuana has negative effects on the male sexual response.
Quitting marijuana can be harder than many long-term marijuana users expect, so you and your partner would be wise to quit as soon as possible, while you still have time to get help before getting pregnant. If either or both parents still use marijuana when the baby arrives, you are increasing the risk that your child may use drugs in the future, and parental drug use is implicated in many difficulties for children and families.
Of course, men who smoke marijuana do get women pregnant. But some men are more fertile than others, or are more fertile at different times of their lives. Smoking marijuana, Burkman warns, will make a borderline-infertile man frankly infertile.
“The reason men have millions of sperm is because the fertility process is more difficult than people think,” Dominguez tells WebMD. “The whole process of ascending up the tract to the fallopian tubes and then finding the egg is delicately balanced.”
Oct. 13, 2003 — Smoking marijuana makes sperm less fertile — even if the woman is the one who smokes it, a new study shows.
Marijuana and Fertility Timing
“When women smoke marijuana, nicotine, or other drugs, their reproductive fluids contain these drugs,” Burkman says. “The woman smoking marijuana is putting THC into her oviduct, into her cervix. If the man is not smoking but the woman is, his sperm go into her body and hit THC in the vagina, oviduct, and uterus. Her THC is changing his sperm.”
As the sperm approaches the egg, it receives a signal to start swimming — hard. This hyperactivation lets it push through the egg cover. Pooped out sperm don’t have a chance. Learn about more ways marijuana can affect fertility.
“Marijuana-smoking men’s sperm are hyper. They are way out there,” Burkman tells WebMD. “They already have begun the vigorous swimming called hyperactivation. Sperm should be quiet at first. They should be waiting to be washed into cervix and approach the egg before they start hyperactivation.”
Burkman’s team studied only men. But she says that when women smoke marijuana, the active ingredient — THC — appears in their reproductive organs and vaginal fluids. Sperm exposed to this THC are likely to act just as sperm exposed to THC in the testes.
Apart from being important for healthy development, the endocannabinoid system also plays a crucial role in the functioning of sperm.
The endocannabinoid system is responsible for many of our vital biological functions. It contains receptors known as CB1 receptors, found primarily in the central nervous system and the brain, and CB2 receptors found elsewhere in the body.
A 2018 study conducted at Duke University Medical Center has found that regular marijuana use is associated with changes in the genetic profile of sperm. This research is timely, as cannabis legalization is now spreading at an exponential rate.
The Endocannabinoid System, Development, and Fertility
Current research suggests that smoking cannabis affects sperm in notable ways. Firstly, it could reduce sperm count and affect morphology.
The endocannabinoid system may also play a part in the development of the brain. CB1 receptors are prevalent in areas of the brain such as the hippocampus, which is responsible for memory and learning, the basal ganglia, and the cerebellum, which control motor function.
Its small sample size limited the study itself, and there are plans to carry out a larger-scale trial in the future. The authors also intend to investigate whether these genetic changes are reversible and study the effects on the offspring of marijuana users by analyzing blood from newborn babies’ umbilical cords.
There is also some evidence that there are differences in the endocannabinoid systems found in the sperm of infertile men compared with their fertile peers. The authors of that particular study say that their research “identified unprecedented alterations of the ECS in infertile sperm, that might impact on capacitation and acrosome reaction, and hence fertilization outcomes.”