5 Things That Can Harm Your Fertility

When you're trying to conceive, it’s easy to focus on ovulation and timing — but reproductive health is influenced by far more than your fertile window.

Hormones, metabolic health, oxidative stress, sleep and environmental exposures can all play a role in both female and male fertility. While lifestyle changes can’t guarantee pregnancy, understanding the factors that may affect reproductive health can help you make informed choices while trying to conceive.

1. Chronic Stress and High Cortisol

Stress itself doesn't mean you won't get pregnant. But prolonged, significant stress can affect the hormonal systems involved in reproduction.

Cortisol is released as part of the body's stress response. When stress becomes chronic, persistently altered stress-hormone signalling can interact with the hypothalamic-pituitary-gonadal (HPG) axis — the system responsible for regulating reproductive hormones including FSH and LH.

In women, disruption of this signalling may contribute to changes in menstrual cycles and ovulation. In men, chronic psychological stress has also been associated with changes in testosterone and poorer semen parameters.

This isn't a reason to become stressed about being stressed. Instead, think about the basics: regular movement, adequate sleep, time outdoors and finding realistic ways of reducing prolonged stress where possible.

2. A Poor Diet, High Sugar Intake and Metabolic Health

There is no single "fertility diet", but what you eat can influence metabolic health, inflammation and oxidative stress.

Diets dominated by ultra-processed foods, refined carbohydrates and added sugars may contribute to insulin resistance. This is particularly relevant in polycystic ovary syndrome (PCOS), where insulin resistance can contribute to increased androgen levels and disruption of normal ovulation.

Oxidative stress is another important area of fertility research. It occurs when the production of reactive oxygen species exceeds the body's antioxidant defences and has been investigated in relation to both egg and sperm function.

Rather than chasing individual "fertility superfoods", focus on an overall balanced diet containing:

• Plenty of fruit and vegetables

• Wholegrain and high-fibre carbohydrates

• Healthy fats from foods such as nuts, seeds and olive oil

• Good-quality sources of protein

• Adequate hydration

Supplements can support your nutritional intake, but they shouldn't replace a varied, balanced diet.

3. Smoking and Excessive Alcohol

Smoking has one of the clearest associations with poorer reproductive health.

Cigarette smoke exposes the body to numerous chemicals and increases oxidative stress. In women, smoking has been associated with reduced fertility and adverse effects on ovarian function. In men, it has been linked with poorer sperm concentration, motility and increased sperm DNA damage.

Alcohol is slightly more complicated, particularly at lower levels of consumption, but heavy alcohol intake can interfere with reproductive hormones in both men and women.

In the UK, the safest approach if you're pregnant or planning a pregnancy is not to drink alcohol, in line with NHS guidance.

If either partner smokes, stopping is one of the most meaningful lifestyle changes you can make when preparing for pregnancy.

4. Poor Sleep and Disrupted Circadian Rhythms

Sleep isn't simply downtime. It's closely involved in hormonal regulation, metabolism and cellular repair.

Our circadian rhythm helps regulate the timing of numerous hormones throughout the body. Regular sleep deprivation, night shifts and chronically disrupted sleep patterns have therefore become an increasing area of interest in reproductive research.

Melatonin, best known as the hormone involved in regulating the sleep-wake cycle, also has antioxidant properties and is naturally present within ovarian follicular fluid. Researchers have investigated its potential relationship with oxidative stress and reproductive function.

That doesn't mean you need a perfect eight-hour sleep every night to conceive. But consistently prioritising good-quality sleep is worthwhile for overall metabolic, hormonal and reproductive health.

Aim for a reasonably consistent sleep-wake schedule and around 7–9 hours of sleep where possible.

5. Endocrine-Disrupting Chemicals

This is one of the less talked-about areas of reproductive health.

Endocrine-disrupting chemicals (EDCs) are substances capable of interfering with the body's hormone systems. Examples include bisphenols such as BPA and certain phthalates, which can be found in some plastics, food packaging, cosmetics and other everyday products.

Because reproductive function is heavily hormone-dependent, researchers have investigated whether higher exposure to certain endocrine disruptors may be associated with outcomes including altered ovarian function and semen quality.

You cannot — and don't need to — eliminate every chemical from your life. But there are simple ways to reduce unnecessary exposure:

• Use glass or stainless-steel containers where practical

• Avoid heating food in plastic containers

• Wash fruit and vegetables before eating them

• Reduce unnecessary use of heavily fragranced products if you wish

• Don't obsess over achieving a completely "toxin-free" lifestyle — it isn't realistic

Supporting Your Fertility From the Inside Too

Lifestyle is only one part of the fertility picture. Preconception nutrition matters too.

Folate and vitamin D both have established roles in the body, while nutrients such as CoQ10 have been extensively studied in fertility and reproductive research.

This is exactly why we created CORE3.

Rather than another multivitamin containing dozens of ingredients at small doses, CORE3 focuses on the 3 most studied nutrients in fertility science:

450 mg CoQ10
4,000 IU Vitamin D3
1,000 µg Methylfolate (5-MTHF)

All in one capsule a day.

CORE3 is doctor-created, UK manufactured, vegan, halal and third-party tested — designed for people looking for targeted preconception nutritional support without taking handfuls of separate supplements.

And due to popular demand, we now also ship worldwide, including the USA!

Discover CORE3 →

Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle. If you have been advised to take prescribed folic acid or other medication, continue this unless your healthcare professional advises otherwise.