One more reason couples should avoid using recreational drugs when trying to conceive: Researchers from the University of California, San Francisco, have found that exposure to marijuana could lead to infertility. Published February 5, 2010, in the journal Cell, the study detailed the intricate number of biochemical changes sperm undergo as they become activated for egg fertilization.
According to researchers, human spermatozoa are completely still in the acidic (low pH) environment of the male reproductive system, but once ejaculated during intercourse, the higher pH (alkaline) environment of the female reproductive tract triggers rapid changes in sperm that allow individual spermatozoa to move, mature, and prepare for fertilization. Helping this process along is endocannabinoid anandamide—a substance released by female reproductive tract neurons and the egg membrane. Cannabinoids naturally found in marijuana ("cannabis") may mimic endocannabinoid, researchers believe, causing sperms to mobilize while still in the male reproductive tract.
"Marijuana likely activates sperm prematurely, leaving them (burned) out in a matter of hours," says Yuriy Kirichok in a statement to United Press International (UPI).
Smoking pot and pregnancy just don't mix—for men or women. Other studies show that marijuana use during pregnancy can shorten the length of pregnancy, negatively influences the quality and duration of labor, impairs fetal growth, and may contribute to in the newborn.
According to the March of Dimes, some babies who were regularly exposed to marijuana during pregnancy may have withdrawal-like symptoms after birth (crying, trembling, and trouble sleeping). The March of Dimes also notes that children exposed to marijuana in the womb may have problems paying attention when they reach school age.