Lifestyle and fertility

Body weight is one of the most significant modifiable factors affecting fertility for both women and men:

For women:

Underweight (BMI <18.5):

• Can cause irregular or absent periods
• May prevent ovulation (hypothalamic amenorrhea)
• Associated with lower egg quality
• Increases miscarriage risk

Overweight/Obese (BMI >25):

• Disrupts hormone balance
• Increases risk of ovulation disorders
• Associated with PCOS
• Reduces IVF success rates
• Increases pregnancy complications

Optimal range:

A BMI of 18.5-24.9 is associated with the best fertility outcomes, though fertility is possible across a range of body sizes.

For men:

• Obesity reduces testosterone levels
• Increases oestrogen (converted from fat tissue)
• Associated with lower sperm count and motility
• Increases DNA fragmentation in sperm
• Affects erectile function

What the research shows:

• Losing 5-10% body weight can restore ovulation in many women with weight-related fertility issues
• Weight loss improves IVF success rates
• Changes in sperm quality may take 3+ months to appear after weight loss
• Extreme dieting can temporarily worsen fertility

The balanced approach:

Focus on sustainable, healthy eating and regular exercise rather than crash dieting. Gradual weight changes are more beneficial for fertility than rapid fluctuations.

What you eat can influence your fertility:

Dietary patterns associated with better fertility:

Mediterranean-style diet:

• Rich in vegetables, fruits, whole grains
• Healthy fats (olive oil, nuts, fish)
• Moderate lean protein
• Limited processed foods
• Associated with improved fertility in studies

The "fertility diet" research:

Harvard's Nurses' Health Study identified dietary factors associated with reduced ovulatory infertility:

• Monounsaturated fats over trans fats
• Plant protein alongside animal protein
• High-fat dairy over low-fat
• Complex carbohydrates over refined
• Adequate iron

Key nutrients for fertility:

Folic acid (400mcg daily): Essential for women to reduce neural tube defects. Start before conception.

Iron: Important for ovulation. Plant sources or supplements if needed.

Omega-3 fatty acids: Found in fish, support egg quality and sperm health.

Antioxidants (vitamins C, E, zinc, selenium): Protect eggs and sperm from oxidative damage.

Vitamin D: Deficiency is common and may affect fertility.

What to limit:

• Trans fats: Found in some processed foods; strongly associated with reduced fertility
• Excess sugar: High glycemic foods may affect ovulation
• Processed foods: Generally associated with poorer outcomes
• Excessive caffeine: Limit to 200mg daily (about 2 cups of coffee)

For men:

Antioxidant-rich diets are particularly important for sperm health. Zinc, selenium, and vitamins C and E support sperm quality.

These common substances have varying effects on fertility:

Smoking:

The evidence is clear - smoking significantly harms fertility:

For women:

• Accelerates egg loss (early menopause by 1-4 years)
• Reduces IVF success rates by 40-50%
• Increases miscarriage risk
• Harms developing baby

For men:

• Reduces sperm count by 13-17%
• Impairs motility and morphology
• Increases DNA damage
• Affects erectile function

The bottom line: Quit before trying to conceive. Fertility improves within months of quitting.

Alcohol:

For women:

• Heavy drinking clearly impairs fertility
• Moderate drinking effects are less clear
• Guidelines suggest abstaining when trying to conceive and during pregnancy
• No "safe" amount during pregnancy

For men:

• Heavy drinking reduces testosterone and sperm quality
• Moderate consumption may have less impact
• Reducing intake supports fertility

Recommendation: Limit alcohol significantly when trying to conceive. Women should ideally abstain.

Caffeine:

Moderate caffeine (up to 200mg/day) appears acceptable:

• About 2 cups of regular coffee
• Or 4 cups of tea

Higher consumption may:

• Slightly reduce fertility
• Increase miscarriage risk (evidence mixed)

Practical advice: Limit to 1-2 caffeinated drinks daily when trying to conceive.

Cannabis and recreational drugs:

• Cannabis reduces sperm count and may affect ovulation
• Cocaine, opioids, and other drugs harm fertility
• Avoid all recreational drugs when trying to conceive

Exercise has a nuanced relationship with fertility:

Benefits of regular moderate exercise:

• Maintains healthy weight
• Improves insulin sensitivity (important for PCOS)
• Reduces stress
• Supports hormone balance
• Improves mood and wellbeing

For women:

Optimal: Regular moderate exercise (150 minutes per week)

• Walking, swimming, cycling, yoga
• Maintains fitness without over-stressing the body

Too much may be harmful:

• Intense endurance exercise can disrupt menstrual cycles
• Very low body fat can stop ovulation
• Marathon runners and elite athletes may have fertility challenges
• Balance intensity with recovery

Signs exercise may be affecting fertility:

• Irregular or absent periods
• Very low body weight
• Excessive fatigue

For men:

• Moderate exercise improves sperm quality
• Supports healthy testosterone levels
• Cycling: Some evidence suggests excessive cycling may affect sperm (heat, pressure)
• Extreme endurance exercise may temporarily reduce sperm count

The balanced approach:

• Aim for 150 minutes of moderate exercise weekly
• Include both cardio and strength training
• Listen to your body
• If training intensely, consider reducing intensity when trying to conceive
• Avoid overheating (hot yoga, saunas) especially for men

Exercise during fertility treatment:

Most clinics recommend:

• Continuing gentle exercise during treatment
• Avoiding high-impact activities during IVF stimulation
• Reducing intensity after embryo transfer

Environmental exposures can affect fertility, though the extent is still being researched:

Heat exposure (primarily affects men):

Sperm production requires temperatures 2-4°C below body temperature. Avoid:

• Hot tubs and saunas
• Tight underwear
• Laptops directly on lap
• Prolonged sitting
• Heated car seats

Endocrine disruptors:

Chemicals that can interfere with hormones:

BPA (Bisphenol A):

• Found in some plastics and can linings
• Reduce exposure by using glass or stainless steel containers
• Avoid heating food in plastic

Phthalates:

• Found in plastics, fragrances, personal care products
• Choose fragrance-free products when possible

Pesticides:

• Wash fruits and vegetables thoroughly
• Consider organic produce for the "dirty dozen"
• Avoid direct contact with pesticides

Practical steps to reduce exposure:

• Use glass or stainless steel food containers
• Don't microwave in plastic
• Choose fragrance-free personal care products
• Wash hands frequently (reduces ingestion of chemicals)
• Filter tap water
• Eat organic when practical (especially for heavily sprayed produce)

Occupational exposures:

Some workplaces have fertility-affecting exposures:

• Chemicals (solvents, pesticides)
• Radiation
• Heavy metals
• Extreme heat

If you work in such environments, discuss protective measures with occupational health.

Perspective:

While it's wise to reduce unnecessary exposures, don't become anxious about every potential risk. Focus on the major modifiable factors (weight, smoking, alcohol) first.

The relationship between stress and fertility is complex:

What we know:

• Severe or chronic stress may affect hormones involved in ovulation
• Stress can reduce libido and frequency of intercourse
• The stress of infertility itself can create a difficult cycle
• Extreme stress (famine, war) clearly affects fertility
• The impact of everyday stress is less clear

What we don't know:

• Whether moderate stress directly prevents conception
• The exact mechanisms by which stress might affect fertility
• Whether stress reduction treatments directly improve fertility

The nuanced view:

While "just relax and it will happen" is unhelpful and often wrong, managing stress is worthwhile for:

• Overall wellbeing
• Quality of life during the fertility journey
• Relationship health
• Maintaining perspective

Stress management strategies:

Mindfulness and meditation:

• Apps like Calm, Headspace, or fertility-specific options
• Even 10 minutes daily can help

Physical activity:

• Reduces stress hormones
• Improves mood
• Provides distraction

Social support:

• Talk to understanding friends and family
• Join support groups (online or in-person)
• Don't isolate yourself

Professional help:

• Consider therapy or counselling
• Cognitive behavioural therapy is effective
• Some fertility clinics offer psychological support

Setting boundaries:

• Limit fertility-related conversations if needed
• Take breaks from trying intensively
• Protect yourself from insensitive comments

The bottom line:

Focus on stress management for your wellbeing, not because "stress causes infertility." You're not responsible for your fertility challenges, and relaxation alone won't necessarily solve them - but feeling better emotionally matters.