Marijuana May Hurt Couples' Conception Odds

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Studies find fertilization inhibited by compound that resembles cannabis

In a finding that could send shivers down the spines of pot-smoking couples hoping to conceive, new research is raising the possibility that marijuana could interfere with reproduction.

New studies show that a cannabis-like compound inhibits the ability of human sperm to fertilize an egg. Also, high concentrations of THC -- the psychoactive ingredient in marijuana -- appear to cause structural changes in sperm as they become ready and able to reach and fuse with a woman's egg.

While pot smoking may not yet qualify as a contraceptive, the findings presented yesterday at the American Society for Cell Biology meeting at Moscone Center in San Francisco are some of the first indications that marijuana use could reduce fertility in both men and women.

Previous research has shown a link between heavy pot smoking and low sperm counts. The latest study focuses on a substance called anandamide that is produced by the body and which acts very much like THC on a cellular level.

It is one of a class of substances called cannabinoids that bind to receptors on cells that also respond to THC. Cannabinoids are found throughout the body and their affect on various systems is only now being studied.

In a series of experiments, researchers at the University of Buffalo-SUNY found that a synthetic form of anandamide reduced by half the number of sperm that were able to attach to a human egg. Furthermore, high concentrations of anandamide slowed down sperm's swimming ability, while low levels kicked it into overdrive.

The researchers also bathed human sperm in solutions containing either THC or anandamide and found that both substances significantly altered the normal structural changes sperm go through as they prepare to approach and bind with an egg.

FREQUENT USE MAY CAUSE TROUBLE
"For people who are very heavy marijuana users, there may be reproductive consequences associated with that," said Herbert Schuel, a professor of anatomy and cell biology at the University of Buffalo and lead author of the study.

More generally, Schuel said, it is possible that glitches in the normal anandamide system could be linked to some cases of unexplained infertility.

Gregory Kopf, a professor in the obstetrics and gynecology department at the University of Pennsylvania, said he was intrigued by the findings, but added that he was not sure that the concentrations of anandamide used in the experiments would ever be reached in the reproductive tracts of people who smoke pot.

Kopf's research focuses on the signals between cells that occur when an egg is fertilized and begins to divide into an embryo.

Although there have been anecdotal reports of marijuana's adverse effect on fetal development and fertility, there have been virtually no formal studies to show whether or not a link exists, said S.K. Dey of the University of Kansas Medical Center.

A COMPOUND'S COMPLEX EFFECTS
Dey has shown that, in mice, excessive amounts of anandamide or an unusually large number of receptors for it on an embryo increases the risk that the fetus will miscarry. Furthermore, he said, in a normal mouse pregnancy, the number of the receptors and the level of anandamide both go down just before the embryo is implanted.

Dey has followed Schuel's research and said he is one of the few scientists focusing on cannabinoids and their effects on the human body outside of the brain.

"People have gotten so focused on the brain function (of anandamide and related compounds) and very little focus has been on its effect on early pregnancy," he said.

Schuel said the federal government's restrictive stance on marijuana- related research has hindered the field. But he said it is attracting more interest as scientists learn more about how cannabinoids affect everything from circulation to digestion to cancer.

Source: http://www.mindfully.org/Health/Marijuana-Hurt-Conception.htm

Category: endometriosis, IVF, IVF-ET, Male Fertility, NORIF, SCORIF, TUFT