By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 03/17/2015

Marijuana decreases male fertility by draining the spermatozoids before they reach the egg. This causes fertility problems and reduces the chances of pregnancy.

It has been shown in a recent study that, when men consume marijuana with relative frequency, their spermatozoids’ energy expenditure gets higher, that is to say, spermatozoids need more energy to be able to reach and fertilize the egg. This energy expenditure makes spermatozoids slower and prevents them from fertilizing the egg.

Marijuana

The mentioned article has been published by the scientific magazine Cell. The study upon which it is based was conducted by the University of California, under command of the researcher Yuriy.

Energy to reach the egg

Spermatozoids are male sexual cells whose main goal is to fertilize the egg, which is 10.000 times bigger than them. For a spermatozoid to be able to fertilize the egg, it needs a strong energy input because it has to penetrate the outer protective membranes of the egg.

That is the reason why it is important for the spermatozoids not to lose too much energy while inside the male reproductive tract. They need to have enough energy to swim through the long and complex female reproductive path and reach the egg.

Effect of Cannabinoids

The internal PH of spermatozoids is fundamental and changes once spermatozoids enter the female reproductive tract. The membrane channel opens and produces physiological changes that stimulate sperm movement. The cellular channel through which protons pass is called “pore Hv1”. This channel allows protons to pass through, though altering the pH.

Marijuana effects on fertility

Endocannabinoids are lipids produced naturally by the organism and located around the egg. These substances activate cannabinoid receptors. Cannabinoids are the main marijuana component.

An endocannabinoid found in both male and female reproductive tracts is called anandamide. According to Dr. Kirichok, the anandamide can produce physiological changes in male reproductive cells.

Marijuana and its effect on fertility

Cannabinoids, active components of marijuana, alter sperm physiology while still inside the male tract. This makes the spermatozoids spend more energy. Once they reach the female reproductive tract their energy levels are low and they are not strong enough to move and penetrate the egg, fertilizing it.

Marijuana is connected with male infertility and low changes of pregnancy. It might be one of the reasons why some couples cannot achieve pregnancy.

According to some studies, the consumption of marijuana by women can also cause spermatozoids to move more slowly once inside the female reproductive system. On the other hand, some studies connect marijuana consumption with the risk of an ectopic pregnancy.

Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Embryologist
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information