Marijuana could affect fertility in women AND men, researchers warn

by | Jun 10, 2019 | UK Fertility News

Marijuana could affect fertility in women AND men: Researchers warn the drug affects sperm count, ovulation and odds of conceiving. THC, the psychoactive compound responsible for the ‘high’ feeling associated with marijuana, acts on receptors in the reproductive organs of men and women.
By Mary Kekatos Health Reporter For

Men who use pot may have reduced sperm count and volume, and even abnormally shaped sperm. Women who used weed had higher rates of menstrual cycle delays and cycles with no ovulation occurring.

Marijuana could be linked to fertility issues in women and men, researchers warn.

The drug, now legal in most US states and all of Canada, has been tipped as a therapeutic for all kinds of ailments, with one study even suggesting it could boost sperm counts.

But researchers at Western University in London, Ontario, Canada, say the broad picture of evidence suggests cannabis is linked to decreased sperm counts, hampered ovulation and reduced odds of conceiving.

The team is now calling for more research into how the drug affects reproductive health, especially because of increased use in US states and countries where pot is legalized.

Here are five things couples who are looking to get pregnant should consider when it comes to marijuana use:


  • Tetrahydrocannabinol (THC) is the psychoactive compound responsible for the euphoric, ‘high’ feeling often associated with marijuana.
  • THC interacts with CB1 receptors in the central nervous system and brain and creates the sensations of euphoria and anxiety.
  • Studies have shown that THC acts on receptors not just found in the brain but in the reproductive organs of both males and females.


  • Past studies has found that semen quality, and male fertility, can be negatively affected by marijuana use.
  • A 2011 study found that men who smoked marijuana more than once a week saw their total sperm count decrease by almost 30 percent.
  • And an October 2018 study looked at semen samples from more than 400 men screened for infertility.
  • Men who had used cannabis at least once had less volume and a decreased motile count, meaning how sperm that can move, researchers told at the time.
  • The men were also at an increased risk of sperm that was abnormally shaped, which can affect its ability to reach and penetrate an egg.
  • Although how pot affects sperm is not exactly understood, new research has shown the drug may alter DNA, leading to worse sperm quality.


  • A 2007 study in the Journal of Women’s Health looked at more than 200 women and found that occasional marijuana use was linked to menstrual cycle delays of up to three-and-a-half days.
  • Another study found that moderate-to-heavy marijuana users were more likely to have anovulatory menstrual cycles, meaning no ovulation occurs.
  • Researchers believe pot use may disrupt the release of gonadotropins, hormones that stimulate the ovaries, and thereby affect menstrual cycles.
  • However, other lifestyle factors could be having an effect on fertility, said Dr Sara Ilnitsky, a reproductive endocrinology and infertility fellow at Western University.
  • ‘If someone already has some underlying fertility problem, if you’re then also reducing the amount of sperm available or changing when the egg is being released, that could further impact your ability to get pregnant,’ she told the Canadian Press.


  • A 2018 study from Boston University found that marijuana doesn’t lower a couple’s chances of getting pregnant.
  • After accounting for variables such as frequency of intercourse, the researchers  found that the probability of conceiving after 12 menstrual cycles was similar among couples who used cannabis than those who didn’t.
  • And a data analysis from the National Survey of Family Growth found that neither pot use nor frequency of pot use affected time to pregnancy.
  • But the team of the new study says that the results are likely from couples that are not experiencing fertility issues.
  • ‘For couples with infertility, the changes in ovulatory function and sperm count associated with smoking marijuana could compound their difficulty with conceiving,’ they wrote.


  • Currently, 10 states and Washington DC, have legalized recreational weed and 33 states have legalized medical marijuana.
  • Studies that have looked at cannabis and fertility are most small and non-randomized, the researchers point out.
  • Additionally because there different concentrations and strains of pot, that also can confound the data.
  • ‘Reliance on self-reported marijuana use introduces inaccuracy, especially where the drug is illegal, and omits valuable information on route and dose,’ they write. ‘The findings should be interpreted with caution.’
  • While the team suggests that men and women cut out recreational marijuana use altogether if they’re looking to get pregnant, anyone who is using the drug therapeutically would need to have a risk-benefit discussion with a fertility doctor before stopping use completely.

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