Sildenafil and Fertility: Can Viagra Affect the Ability to Conceive?

Many people associate Viagra primarily with erectile dysfunction (ED), but could this medication play a role in fertility? Does Viagra affect sperm quality, ovulation, or implantation, and can it influence pregnancy outcomes for men or women trying to conceive? How is Viagra used in fertility treatments, and what are the possible side effects or complications?

This guide examines these questions, including their effects on the endometrium, immune system, and semen parameters. It also explores how Viagra is used off-label in reproductive medicine, the forms and dosages commonly studied, and what clinical evidence exists to support or refute its impact. Let’s dive in.

What Is Viagra and How Does It Work?

Viagra, containing sildenafil citrate as its active component, was accidentally discovered in the late 1980s by Pfizer scientists while originally being tested for angina (chest pain caused by heart disease). During clinical trials, men noticed it induced erections as a side effect, which led to its development as the first oral treatment for impotence. The FDA approved Viagra in March 1998 [1].

Now that the original patent has expired, multiple generic sildenafil versions are available, increasing competition and significantly lowering costs compared to brand-name Viagra. Generic options maintain the same efficacy and safety, making this effective medication more accessible than ever.

Viagra works as a phosphodiesterase‑5 (PDE5) inhibitor, improving blood flow by relaxing vascular smooth muscle. In men, when sexually aroused, this mechanism enhances penile blood flow, which helps to achieve and maintain an erection. It works by selectively inhibiting PDE5 in the penis, which improves the effects of nitric oxide (NO).

NO triggers the production of cyclic GMP (cGMP), a chemical messenger that signals the smooth muscles around blood vessels to relax, allowing blood to flow in and produce an erection during sexual stimulation. By blocking PDE5, Viagra prevents the breakdown of cGMP, keeping this “relax and fill with blood” signal active longer.

Sildenafil’s pharmacological action does not directly alter hormonal pathways or spermatogenesis, and is not approved by the FDA as a fertility drug. Its primary label indication is for treating impotence; however, it is also used under medical direction for pulmonary hypertension and, in some reproductive medicine settings, off-label as part of fertility protocols.

Does Sildenafil Affect Fertility?

Fertility refers to the biological ability to conceive and carry a pregnancy to term. In female fertility, this involves healthy ovulation, a receptive endometrium, and proper hormonal regulation, while male fertility depends on sufficient sperm count, motility, morphology, and delivery to the female reproductive tract. Disruptions in these processes can decrease the likelihood of conception, creating a real mess of emotions, appointments, and medication schedules.

Sildenafil and fertility do not generally worsen these issues and may help by improving endometrial thickness or erectile function. In women, vaginal sildenafil can increase uterine blood flow, enhancing endometrial thickness (>7 mm is linked to higher pregnancy rates) and potentially improving implantation. Some trials report higher clinical and biochemical pregnancy rates when used with ovulation induction agents like clomiphene citrate or estradiol valerate [2][3]. It is used in ART cycles, particularly for women with a thin endometrium (<7 mm), though optimal dosing and timing are still under study.

It may also reduce excessive natural killer (NK) cell activity, making the uterine environment more receptive. Unlike ED use, sildenafil for fertility is prophylactic rather than situational—it is not taken immediately before intercourse but administered over several days or weeks to optimize the endometrium for implantation. Most studies use vaginal suppositories, though oral sildenafil (25–100 mg daily) has also been studied, with ongoing research on optimal dosing and timing.

Mechanistically, sildenafil not only increases endometrial thickness but also improves uterine and ovarian blood flow, enhancing oxygen and nutrient delivery to the endometrium, which may support implantation. In men, typical sildenafil use does not impair sperm parameters and may help with stress-related ED without affecting fertility [4].

Laboratory data show rare premature acrosome reactions, which could impact fertilization in assisted reproduction [5]. Overall, taking sildenafil is not associated with reduced fertility in women or men and is not contraindicated for couples trying to conceive [6]. Since it is not FDA-approved for fertility treatment, off-label use should be discussed with a healthcare provider.

Possible Side Effects After Taking Viagra?

Like any medication, Viagra can cause side effects, though not everyone experiences them. Most adverse effects are mild and temporary, typically arising from the drug’s vasodilatory action, which increases blood flow in various tissues. The likelihood and severity of side effects can vary with dose and individual sensitivity, making awareness important, especially when sildenafil is used in fertility treatments alone or with other medications. Common side effects include [7]:

• headache;
• flushing;
• nasal congestion;
• indigestion;
• visual changes;
• dizziness.

These are usually short-lived and resolve without intervention. Improper dosing or combining medications without guidance could cause problems in fertility treatment or daily life. More serious events are rare but may involve significant hypotension, cardiac symptoms, or allergic reactions. Since sildenafil is often used alongside fertility drugs like clomiphene citrate, estradiol, or gonadotropins, careful monitoring by a specialist is essential to prevent problems and ensure treatment is safe and effective.

Use During Pregnancy and Breastfeeding

Sildenafil is not FDA-approved for pregnancy or breastfeeding. Pre-pregnancy use under specialist supervision may improve endometrial thickness, but continuation during confirmed pregnancy requires careful maternal-fetal risk assessment. Limited safety data exist for breastfeeding.

Conclusion

Sildenafil and fertility are not intrinsically antagonistic. For women, sildenafil supports fertility by improving uterine blood flow, increasing endometrial thickness, and possibly modulating uterine immune activity. This enhances embryo implantation. Clinical results are promising but inconsistent, and sildenafil is not approved as a standard fertility treatment.

Most fertility studies use vaginal suppositories, which are compounded formulations not commercially available, though oral tablets are an alternative. Dosage regimens differ from those used for erectile dysfunction, typically administered over several days or weeks during the menstrual cycle rather than immediately before intercourse.

For men, sildenafil is not bad but generally fertility-neutral and does not harm sperm parameters. It may indirectly assist conception by improving erectile function, reducing the stress associated with infertility, and supporting sexual activity. While off-label, sildenafil can be incorporated safely under medical supervision.

Patients should always consult a fertility specialist to determine individualized dosing, timing, and monitoring, and to explore cost-saving options for compounded formulations. Decisions about using sildenafil as part of fertility care should be made with careful assessment of reproductive goals, risks, and overall treatment strategy.

References:

1. After 20 years, Viagra has impacted so much more than just sex. By Quartz Staff. Retrieved: February 1, 2026. Qz.com.
2. Does Viagra Affect Fertility in Women? What to Know About Viagra as a Possible Fertility Treatment. By Jill Barat. Reviewed by Patricia Pinto-Garcia. Published: February 24, 2025. Goodrx.com.
3. Effect of sildenafil citrate on treatment of infertility in women with a thin endometrium: a systematic review and meta-analysis. By Xin Li, Ting Luan, Chun Zhao, Mianqiu Zhang, Li Dong, Yan Su, and Xiufeng Ling. Published: November 2020. Pmc.ncbi.nlm.nih.gov.
4. Sildenafil’s impact on male infertility: what has changed in 20 years? By Nickolas D. Scherzer, Tan V. Le, and Wayne J. G. Hellstrom. Published: March 5, 2019. Nature.com.
5. Viagra may affect Fertility. Published: April 1, 2004. Britishfertilitysociety.org.uk.
6. Pregnancy, breastfeeding and fertility while taking sildenafil. Retrieved: February 1, 2026. Nhs.uk.
7. Side Effects of Viagra: What You Need to Know. By Helen Marshall. Medically reviewed by Alex Brewer. Retrieved: February 1, 2026. Healthline.com.