Vaping vs Smoking's Effects on Male Fertility

Vaping vs Smoking's Effects on Male Fertility

Men who swapped cigarettes for vaping during IVF saw better sperm motility and fewer miscarriages, but experts warn that vaping is not risk-free for hopeful parents.

In a study recently published in the journalScientific reportsResearchers evaluated whether exclusive electronic cigarette (e-cigarette) alters ore semen quality and live birth outcomes compared to traditional cigarette smoking in couples undergoing in vitro fertilization (IVF).

The study did not include a non-smoker control group, so the results compare e-cigarette users specifically to conventional cigarette smokers, not non-smokers.

background

Despite decades of anti-smoking campaigns, about a third of men of reproductive age still smoke conventional cigarettes. Meanwhile, sleek e-cigarettes that heat-flavored nicotine liquids are becoming increasingly popular and marketed as safer. Traditional smoking is firmly linked to lower sperm counts, reduced motility and higher rates of miscarriage, but the reproductive impact of electronic aerosols rich in metals and aldehydes remains poorly defined.

Couples investing in costly IVF worry whether switching from smoke to steam truly protects fertility or merely changes the risk profile. Comparative evidence, particularly within assisted reproductive technology, is limited and further research is needed to clarify these uncertainties.

About the study

Medical records from an infertility clinic were reviewed between May 2022 and January 2024 for 296 couples who underwent IVF or intracytoplasmic sperm injection. The male partners had smoked exclusively conventional cigarettes or e-cigarettes for at least six months and provided semen after two to seven days of abstinence.

The study included couples in which the woman's infertility was due to tubal disease, polycystic ovary syndrome, thyroid dysfunction, hyperprolactinemia, or previous failed intrauterine insemination. Each female participant was a confirmed non-smoker.

Researchers excluded participants with advanced maternal age, endometriosis, adenomyosis, poor ovarian response, recurrent pregnancy loss, congenital genitourin anomalies, severe male factor infertility, or any history of switching between cigarette types. Only the first or second embryo transfer cycles were included to avoid confounding by recurrent implantation failures.

They then performed a standard semen analysis, calculated body mass index, tested serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, prolactin, anti-Müllerian hormone (AMH) and sex hormone binds (Shbg) and demanded under one Gnonadototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototo tototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototototot ,es Ovarian (AMH) and demanded. Antagonist protocol, 36 hours after a recombinant human chorionic gonadotropin (RHCG) vaccine.

All embryos were cryopreserved as blastocysts and transferred in frozen cycles. Outcomes included categories of pregnancy, miscarriage and live birth, and semen parameters. Chi-square and independent t tests were used to compare groups, and logistic regression identified live predictors with a P value ≤ 0.05.

Study results

Male partners in the conventional cigarette (n = 151) and e-cigarette (n = 145) groups have comparable body metrics and most hormonal parameters, but divided into three laboratory values. Traditional smokers showed higher serum prolactin (13.84 ± 5.97 ng/ml vs 13.02 ± 4.80 ng/ml; p = 0.029) and higher sperm concentration (81.55 ± 57.19 × 10⁶/ml vs 71.78 ± 44.40 ± 57.19 × 10⁶/ml). vs 71.78 ± 44.40 × 10⁶/ml; (48.91 ± 11.75% vs. 48.15 ± 13.29%; p = 0.014); Semen volume, leukocyte count and strict morphology did not differ (p>0.10).

Female partners in both cohorts were similar in age and ovarian reserve indices. However, their body mass index was slightly higher when the male partner smoked conventional cigarettes (23.38 ± 4.29 kg/m²) compared to vapor (22.16 ± 3.47 kg/m²; p = 0.017). The controlled ovarian stimulation was uniform: stimulation lasted 9.6 ± 1.5 days with a total gonadotropin dose of 2,385.68 ± 1,047.71 IU in smokers and 2,338.45 ± 898.18 IU in vapers producing comparable oocytes, and with and g. Two-pronuclei embryos (11.23 ± 7.00 vs. 11.28 ± 6.75; all p > 0.38).

The pregnancy endpoints diverged only after ultrasound confirmation. Biochemical pregnancy, clinical pregnancy, ongoing pregnancy, and biochemical miscarriage were statistically indistinguishable (p ≥ 0.16). Male partners who vaped rather than smoked were associated with a decrease in ultrasound participation from 36.3% to 12%, a relative reduction of about two-thirds (p < 0.001). At the same time, live birth rates rose from 41.1% to 55.9%, which corresponds to an absolute increase of 15 percentage points (p = 0.011).

Multivariable logistic regression for all 296 couples showed two independent live birth predictors: every 1 miu/ml increase in male serum FSH increased the odds by 19% (adjusted odds ratio 1.19, 95% confidence interval 1.06-1.34; 0.05-0.71; this latter result however, is biologically counterintuitive and contradicts the direction observed in univariate analysis. It likely reflects either a statistical artifact or residual confounding and should be interpreted with caution.

Smoking modality, sperm motility, and paternal or maternal body mass index did not retain independent significance after accounting for these laboratory factors.

The authors note that although differences in semen parameters and live birth outcomes were observed between cigarette species, key predictors of full-term birth (such as the number of FSH and 2PN embryos) were not significantly different between groups.

Conclusions

In summary, e-cigarette use by male partners undergoing IVF appears to be less detrimental to reproductive success than continued conventional smoking. Although semen concentration was slightly lower, progressive motility was higher and prolactin was lower in the vapers, resulting in fewer clinical miscarriages and a 15-point gain in live birth rate.

Importantly, cigarette type did not override established predictors such as FSH levels or embryo counts, and vaping is not a guarantee of success.

Crucially, the authors emphasize that these results should not be interpreted as an endorsement of e-cigarette use, as e-cigarettes still pose potential health risks and their long-term effects on reproductive health are not fully understood.

The retrospective design, reliance on self-reported data, lack of information on dietary factors, unmeasured heavy metal exposure, and unaccounted for variability in e-cigarette devices limit any causal inferences and generalizability. Further research, including direct comparisons with non-smokers and more detailed toxicological assessment, is needed to clarify the reproductive risks of e-cigarettes and to guide fertility counseling.

These findings underscore how lifestyle choices can continue to influence assisted reproductive outcomes and support counseling men to quit combustible tobacco while pursuing parenthood more safely.

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