How do smoking and drinking affect fertility?

Men’s Health Mythbuster is a section on UrologyTimes.com that explores common statements and beliefs about men’s health and evaluates whether these statements are false.

In this article, we strive to discuss the impact smoking and drinking can have on fertility. We provide a summary of recent data on these social behaviors and how they may influence reproductive potential.

Cigarettes. While the proportion of smokers has declined, 17.8% of adults in the United States continue to report smoking cigarettes. When looking at gender differences, 20.5% and 15.3% of men and women report smoking, respectively (MMWR Morb Mortal Wkly Rep 2014; 63:1108-12). Cigarette smoking can lead to numerous adverse maternal-fetal health consequences. These can range from preterm delivery, intrauterine growth restriction, to even perinatal mortality (Fertil Steril 2018; 110:611-8). A survey of female employees at a Connecticut hospital found over 95% of respondents knew about the cardiac and respiratory consequences of smoking, but only 27% and 22% were aware of the risks of ectopic pregnancy and infertility, respectively. Public health campaigns have done well at increasing awareness of the more common adverse health consequences of smoking, but further awareness is required for its effect on fertility (Am J Obstet Gynecol 2001; 194:934-9). Smoking can also lead to significant abnormalities with respect to sperm production and semen parameters. These include a reduction in sperm concentration and motility as well as DNA damage. The exact mechanism that leads to sperm impairment is yet to be fully elucidated, but a potential causative agent may be nicotine, which was found to have a dose-dependent deleterious effect on sperm characteristics in male rats (Postgrad Med 2015; 127:338-41; Reprod Biol Endocrinol 2018; 16:3).

Also see: Can finger length predict prostate cancer risk?

Paternal smoking has also been shown to significantly impact the success of assisted reproductive technology (ART) such as in vitro fertilization and even intracytoplasmic sperm injection. Abnormal DNA may be the cause of the failure in the development of the embryo (Fertil Steril 2003; 79:1550-4). Not only is there evidence to support the strong association between smoking and abnormal semen parameters, sperm DNA, and failure of ART, but reports suggest abnormal sperm parameters in males who had exposure to cigarette smoke in utero (Postgrad Med 2015; 127:338-41). Therefore, it is critical from a public health perspective to increase the awareness of not only the more commonly known consequences of smoking but also the adverse effects to reproduction. E-cigarettes contain nicotine to various concentrations, with a study finding nicotine levels even in products that were labeled nicotine-free, suggesting insufficient manufacturing quality control. Given the use of e-cigarettes is quite prevalent among young adults, it is important to counsel patients on the potential impact it may have on reproduction (MMWR Morb Mortal Wkly Rep 2018; 629–33; JAMA 2018; 2039-41).

Next:Marijuana, alcoholMarijuana. Cannabis has become the most popular illicit drug in the United States. It was estimated by the United Nations Office on Drugs and Crime that cannabis use increased from 37.6 million in 2005 to 49.2 million in 2015. Use of cannabis is most prevalent in those less than 35 years old, an age where reproductive potential is most typically of utmost importance.

Read - Alcohol and the prostate gland: Friend or foe?

A systematic review published in 2017 found limited published data evaluating cannabis use and the impact on male factor infertility; however, the small data available demonstrated a negative impact on male reproduction (Fertil Steril 2017; 108:e131-2). Other reviews have reported a decrease in sperm concentration with the use of cannabinoids (Eur Urol Focus 2018; 4:324-8). As an increasing number of states pass legislation to legalize it, more data will be available to evaluate the impact of cannabis on reproduction.

Alcohol. Alcohol use has increased dramatically over the past 2 decades, with excessive intake leading to approximately 88,000 deaths and 2.5 million years of potential life lost each year in the United States from 2006 to 2010 (Alcohol-Related Disease Impact). Given the impact of alcohol on the fetus, it has been recommended that women avoid any alcohol consumption as no safe dose has been identified. With respect to male alcohol consumption, the data are quite varied, with reports having suggested alterations in semen parameters as well as sperm DNA. It is also recommended that males avoid alcohol consumption prior to providing a sample for in-vitro fertilization (Fertil Res Pract 2017; 3:10).

Premal Patel, MD

Ranjith Ramasamy, MD

Dr. Patel is a fellow in reproductive urology and Dr. Ramasamy is director of male reproductive urology and assistant professor of urology at the University of Miami.