If a male is chewing tobacco, can it cause birth defects, or
miscarriages when the female gets pregnant? Also, when quitting
chewing tobacco, how long before the sperm is no longer damaged
by the nicotine (if indeed it ever was)? In other words, how
long should one wait before trying to safely conceive with a male
who is quitting the chewing habit?
Although nicotine does appear to have negative effects on sperm production, I am not aware of evidence suggesting that nicotine use in a man adversely affects the viability of the fetus or causes birth defects. The most significant concern is that your partner's use of tobacco may diminish the viability of his sperm and make it more difficult for you to conceive. What I am saying does not apply to women who smoke or chew tobacco during pregnancy - in this situation we know that tobacco use probably contributes to an increased incidence of miscarriages and fetal abnormalities.
Your partner's decision to quit chewing is a good one. What child wants to see his or her father disfigured or killed by one of those nasty cancers of the head and neck which has been associated with smokeless tobacco use.
I have copied the abstract of a comprehensive review on smoking and male reproduction from the International Journal of Andrology. If you want to explore the medical literature further, take a look at Pub Med:
Int J Androl 1996 Dec;19(6):323-37
Smoking and male reproduction: a review.
Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400, USA.
Because of the large number of men worldwide who smoke and the fact that cigarette smoke contains known mutagens and carcinogens, there has been concern that smoking may have adverse effects on male reproduction. A review of the epidemiological literature indicates that cigarette smoking is associated with modest reductions in semen quality including sperm concentration, motility and morphology. The associations between male smoking and sperm concentration and motility are stronger among studies of 'healthy' men (e.g. volunteers and sperm donors) than among men from infertility clinic populations. Smoking has also been associated with alterations in hormone levels in males, for example increases in the levels of oestrone and oestradiol. Despite modest reductions in semen quality and altered hormone levels among smokers compared to non-smokers, studies have not shown a reduction in male fertility in association with paternal smoking. There is some evidence to suggest that paternal smoking is associated with congenital anomalies and childhood cancer (with ORs in positive studies generally < 2.0). Smoking has not been shown to be mutagenic to human spermatozoa, although studies have been small and have had methodological shortcomings. It is concluded that, although smokers as a group may not experience reduced fertility, men with marginal semen quality who wish to have children may benefit from quitting smoking, since several small studies indicate the potential for improved semen quality after quitting smoking. More research on the benefits of quitting smoking among men with marginal semen quality is needed. Methodological improvements in studies aimed at clarifying the association between paternal smoking and reproductive and developmental outcomes in offspring should include obtaining accurate paternal smoking dose information, evaluating smoking exposure information in relation to various time windows (e.g. prior to conception, during gestation), and controlling for potential confounders and modifying factors such as age and maternal smoking habits. More sensitive and specific laboratory assays and increased sample sizes are required to establish whether smoking induces mutations in human spermatozoa.
For a lot more information about tobacco dependence and smoking cessation, check out my Ask DrSteve web site, conveniently hyperlinked below. Good luck!
Steve Adelman, M.D. (a.k.a. DrSteve)
This information is for general medical education purposes only. Please consult your physician for diagnostic and treatment options pertaining to your specific medical condition.
Keywords:smokeless tobacco, infertility
Ask DrSteve: The Real Story About Smoking, Drinking & Getting High
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