Is metoprolol safe for fertility in reproductive‑age adults?

Metoprolol and Fertility

Metoprolol appears to be safe for fertility in reproductive-age adults, with no established adverse effects on human fertility, though animal studies show reversible effects on spermatogenesis at therapeutic doses. 1

Key Evidence from FDA Drug Labeling

The FDA label explicitly states that "the effects of metoprolol on the fertility of humans have not been studied." 1 However, important animal data exists:

• Metoprolol showed reversible adverse effects on spermatogenesis in male rats starting at oral doses of 3.5 mg/kg (only 0.1-times the human dose when based on surface area) 1
• Despite effects on spermatogenesis, metoprolol had no effect on rates of conception at higher doses in animal fertility studies 1
• No teratogenic potential was demonstrated in reproduction toxicity studies in mice, rats, and rabbits 1

Clinical Context: Pregnancy and Reproductive Age

Metoprolol is considered safe for use during pregnancy, unlike atenolol which should be avoided. 2 The 2025 AHA/ACC hypertension guidelines specifically note:

• Atenolol has been associated with fetal growth restriction and lower fetal weight and should be avoided in pregnancy 2
• This is likely not a class effect, as other beta-1-selective agents like metoprolol have not demonstrated similar associations with growth restriction 2
• Metoprolol and bisoprolol are considered safe in pregnancy and are used in many European countries 3

Research Evidence on Male Fertility

Limited human data suggests potential concerns that require monitoring, though effects appear reversible:

• A 2025 cross-sectional study of over 7,000 men found metoprolol (C07AB02) showed statistically significant associations with low semen quality after adjustment for age and abstinence days 4
• However, this study was limited by self-reported medication use and inability to separate medication effects from underlying disease 4
• A 1998 rat study showed metoprolol (3.5 and 7 mg/kg) induced significant decreases in sperm motility, increased sperm abnormalities, and decreased testosterone levels at first and 30 days after dosing 5
• Critically, all hazard effects were reversible, returning to normal values 60 days after discontinuation 5

Practical Clinical Approach

For men of reproductive age requiring beta-blocker therapy:

• Metoprolol can be used without absolute contraindication for fertility concerns 1
• If semen quality issues arise, consider that effects may be reversible with discontinuation 5
• Avoid atenolol specifically, as it has more established reproductive concerns 2, 6
• Monitor for sexual dysfunction (erectile/ejaculatory dysfunction), which is more commonly associated with beta-blockers than fertility impairment 6

For women of reproductive age:

• Metoprolol is an acceptable choice and safer than atenolol during pregnancy 2, 3
• Metoprolol is excreted in breast milk in very small quantities (less than 1 mg daily for an infant consuming 1 liter) 1

Important Caveats

• The lack of adequate human fertility studies means definitive conclusions cannot be drawn 1
• Animal reproductive toxicity does not always predict human response 1
• The underlying cardiovascular condition requiring treatment may itself impact fertility independent of medication effects 4