It’s no secret that substance abuse can be damaging to your health, but one of the ways that an addiction to a drug or alcohol can be most harmful is in hindering your ability to become a parent. From cigarettes to heroin, here’s what researchers say about addiction’s impact on reproductive health:
Besides harming almost every organ in the body, smoking can have disastrous consequences for fertility. In one study published in the journal Human Reproduction, women who smoked and were trying to get pregnant were 42% more likely to experience a delay in conception of more than one year compared with non-smoking women; in fact, the smokers had double the risk of infertility problems of non-smokers in the study.
Other research has shown that cigarettes impair the ovaries’ ability to make eggs that can be readily fertilized. If you’re a woman who smokes you’re also likelier to have short and/or irregular menstrual cycles, which makes it more difficult to conceive. “Stopping smoking is essential, at least while a pregnancy is planned, to halt the negative effect on ovarian function and increase the chances of spontaneous pregnancy,” wrote the authors of a January 2015 review published in the journal Fertility and Sterility. It isn’t only women’s fertility that’s affected by a nicotine addiction, either: In men, smoking can affect sperm quality — though the encouraging news is that quitting smoking seems to improve sperm within a relatively short time.
Although it’s often seen as a relatively harmless drug, marijuana can have a profound effect on reproductive health, especially in men. In a study of almost 2,000 British guys, researchers found that those 30 and younger who reported smoking marijuana at least once in the past three months were almost twice as likely to have sperm whose shape and size was abnormal. Study author Allan Pacey of the University of Sheffield suggested that “cannabis users might be advised to stop using the drug if they are planning to try and start a family.”
In another study, out of the University of Buffalo, the authors concluded that in men in their study who regularly smoked marijuana sperm moved “too fast and too early,” thereby hurting their ability to penetrate an egg at the optimal time, according to study author Lani J. Burkman, PhD, assistant professor of gynecology/obstetrics and urology and head of the section on andrology in the University of Buffalo School of Medicine and Biomedical Sciences. “These sperm will experience burnout before they reach the egg and would not be capable of fertilization,” Burkman said in a statement.
There’s a lot less data on how pot affects a woman’s fertility. One 1990 study published in Epidemiology found that women who smoked marijuana had a slightly higher risk of infertility due to abnormalities in ovulation (when the egg is released), and that the risk was highest among women who’d used marijuana within a year of trying to get pregnant.
While having an occasional drink likely won’t lower your odds of getting pregnant, it’s a different story if you’re drinking a lot. In a 2005 Fertility and Sterility study, researchers compared sperm quality in moderate drinkers with that of 66 alcoholic men who drank about six ounces or more of alcohol daily, or nearly so. The researchers detected abnormalities in the alcoholics’ reproductive hormones and found that their sperm count and motility (how well the sperm could move through the female reproductive tract) were significantly lower compared with the non-alcoholic control group.
If you’re a woman, drinking a lot can make it much harder to conceive and carry a baby to term (and it can dramatically raise the risk, of course, of the child developing fetal alcohol syndrome). In a study of 7,760 Danish women researchers found that those 30 or older who consumed seven or more drinks per week were about twice as likely to be diagnosed with infertility problems as those who had less than one weekly drink. “It may be important for the female partner in an infertile couple to limit alcohol intake or to not drink at all,” the authors wrote. In another trial, women who said they drank frequently — meaning they consumed at least a couple of bottles of wine or a minimum of half a bottle of hard liquor per week — were more likely to undergo fertility evaluation.
Heroin and Cocaine
When it comes to hard drugs like heroin and cocaine and their impact on fertility, the prognosis is, unsurprisingly, pretty grim. Men who use heroin, for example, may experience sexual dysfunction that lasts even after they quit, suggests a study published in the journal Clinical Endocrinology. Heroin affects the quality, and especially the motility of sperm, according to a study of 80 heroin-addicted men.
The potential effects of cocaine on fertility have mostly been evaluated in animal trials. In one study of female monkeys researchers found that cocaine impaired ovulation and ovarian function. Similarly, a study in male rats showed that cocaine affected the development of the animals’ sperm cells. There’s also some evidence from studies in people linking cocaine use to infertility in men. In one trial cited in a 2012 review, men who’d used cocaine for at least five years were twice as likely to have low sperm motility as non-users. “The use of illicit drugs is … likely adversely impacting the fertility of men who abuse drugs,” concluded the authors of the review.