CLINICAL FEATURE

REVIEW

The effects of cigarette smoking on male fertility

Jason R. Kovac

, Abhinav Khanna

& Larry I. Lipshultz

Urology of Indiana, Male Reproductive Endocrinology and Surgery, Carmel, IN, USA, and

Department of Urology, Baylor College of Medicine,

Houston, TX, USA

Abstract

Cigarette smoking, one of the main causes of preventable morbidity and mortality, has a multi-

tude of well-known side effects. The relationship between cigarette smoking and infertility has

been studied for decades; however, large-scale, population-wide prospective studies are lacking.

The majority of the current literature is in the form of retrospective studies focused on the effects

of smoking on semen analyses. This article discusses the results of these studies and reviews the

postulated mechanisms. The effects of smoking on assisted reproduction and

in vitro

fertilization

outcomes are noted. The consequences of smoking while pregnant on future fertility as well as

the outcomes of second-hand smoke are analyzed. The current evidence suggests that men

should be advised to abstain from smoking in order to improve reproductive outcomes.

Keywords:

Smoking, male infertility, semen parameters,

outcomes, zinc,

in vitro

fertilization

History

Received 18 June 2014

Accepted 6 August 2014

Published online 19 February 2014

Introduction

It has been estimated that over one third of all men globally

smoke some form of tobacco and that 21.6% of American

men smoke cigarettes [1]. Smoking has been linked to a

myriad of adverse health outcomes, including cardiovascular

disease, respiratory disease, and cancer of the lungs, bladder,

cervix, esophagus, kidney, pancreas, and stomach [2]. More

recently, researchers have begun to explore the relationship

between cigarette smoking and reproductive health.

The American Society for Reproductive Medicine defines

infertility as the inability to achieve pregnancy following

12 months of regular, unprotected sexual intercourse [3]. It

has been estimated that up to 15% of all couples attempting

to have children face some form of infertility [4]. Although

almost half of all cases of infertility are due exclusively to

female factors, the male factor is the sole etiology in approxi-

mately 30% of couples. An additional 20% of infertile cou-

ples have a combination of male and female factors. Thus,

male factor infertility plays a significant role in 50% of all

couples with infertility [5]. This review examines the litera-

ture to elucidate the potential effects of cigarette smoking on

male infertility.

Materials and methods

A PubMed/Medline search was conducted of the literature

from 1960 to March 2014. The search was performed using

combinations and derivatives of the following terms:

smok-

ing, male infertility, outcomes, in vitro fertilization, semen

analysis, morphology, prenatal (or) maternal smoking,

and

second-hand smoking

. The Related Citations in PubMed link

from the U.. National Library of Medicine was used to screen

additional abstracts related to the aforementioned searches. In

excess of 1000 manuscripts were screened using title search,

related links, and abstract summaries. Applicable studies

were read and included in this current review.

Effects of smoking on semen analysis parameters

Smoking has been shown to have a detrimental effect on vari-

ous parameters of semen analysis. A cross-sectional analysis of

2542 healthy men from 1987 to 2004 by Ramlau-Hansen et al.

[6] found that on semen analysis, cigarette smokers had lower

semen volumes, sperm counts, and percentage of motile sperm

compared to men who did not smoke. Further, it was suggested

that the relationship between smoking and sperm concentration

was dose-dependent. Indeed, men who smoked

>

20 cigarettes

per day experienced a 19% reduction in sperm concentration

compared with nonsmokers, even after controlling for age,

recent fevers, and duration of abstinence as well as diseases in

reproductive organs. It was concluded that adult smoking

resulted in moderate impairment of semen quality.

In another large cohort of 1786 men undergoing infertility

workup (655 smokers and 1131 nonsmokers), Kunzle et al.

[7] demonstrated that smoking was associated with decreases

in sperm density (15.3%), total sperm counts (17.5%), and

total motile sperm (16.6%) compared with nonsmokers. Fur-

thermore, morphology (percent of normal forms) as well as

ejaculate volume was slightly affected by smoking but not to

any significant degree. Effects on ejaculate volume were

Correspondence: Dr. Jason R. Kovac, MD PhD FRCSC, Male Reproductive Endocrinology and Surgery, 12188-A North Meridian Street, Suite 200,

Carmel, IN, USA. Tel: +1 317 564 5100. E-mail: jkovac@urologyin.com

Ó

2015 Informa UK Ltd.

http://informahealthcare.com/pgm

ISSN: 0032-5481 (print), 1941-9260 (electronic)

Postgrad Med, 2015; 127(3): 338

–

341

DOI: 10.1080/00325481.2015.1015928