Smoking

Smoking, be it first or second-hand smoke, can negatively impact fertility, and smokers take longer to conceive than non-smokers. Cadmium and cotinine are two specific toxins found in tobacco smoke that can reduce sperm quality and egg production. It is also linked to lower sperm count, altered motility and hormonal imbalance in men. Women who smoke are known to reach menopause early and it also increases female infertility.

Alcohol

Heavy drinking increases the time it takes to get pregnant and reduces the chances of having a healthy baby. It can also reduce a man's sex drive (libido) and sexual performance, affect the quality of sperm and cause impotence. For women planning a pregnancy, not drinking alcohol is the safest option since alcohol can also affect ovulation. Binge drinking (more than six standard drinks on one occasion) can cause miscarriage, stillbirth, premature birth, small birth weight, and Fetal Alcohol Spectrum Disorder (FASD).

Caffeine

Caffeine is a stimulant, found in different amounts, in coffee, black and green tea, energy drinks, some soft drinks, and in chocolate. Limiting caffeine is the best way to go when trying to conceive and also during pregnancy. Some studies have found that women who drink large amounts of caffeine may take longer to become pregnant and have a slightly higher risk of miscarriage and low birth weight. For men, high doses of caffeine might affect the quality of sperm but it's unclear if this affects men's fertility.

BMI

For both men and women, a higher or a very low BMI can impact fertility. Infertility rates are 3 times higher in obese women. A higher BMI can cause hormonal imbalances and pregnancy risks in females. Being underweight, on the other hand, is linked to ovarian dysfunction and infertility in women. Obesity in men is linked to lower sperm count and sperm quality. It alters the balance of testosterone and other hormones that can affect sperm count and sperm mobility.

Drug Abuse

For both men and women, recreational drugs such as cocaine, heroin, ecstasy, cannabis, and others can cause infertility and reduce the chance of pregnancy. They can also cause serious problems during pregnancy. All drugs pass into the bloodstream. Some directly affect sperm or eggs and reduce fertility, whereas some others pass directly into the baby's bloodstream across the mother's placenta, which can cause health problems for the baby.

Diet

Diet affects the health of sperm and eggs. Healthy foods to eat include fibre, complex carbohydrates, dark leafy greens, protein from meat and vegetables, beans, dry fruits and other nuts. Women planning a pregnancy should also supplement their diet with micronutrients like folate and iodine, which reduces the risk of birth defects such as spina bifida and cleft palate. Foods to avoid include animal protein in large amounts, trans fats, highly processed foods and hydrogenated oils, and also a reduction in the intake of excess carbs and sugar.

Exercise

Moderate exercise can reduce the risk of infertility and improve sperm quality since poor sperm quality can cause miscarriages. At the same time, one must be wary of overexercise as vigorous physical activity can inhibit ovulation and reduce production of the hormone progesterone.

Sleep

Melatonin is naturally produced by the body during sleep. Any artificial light including device screen light can affect the melatonin production. A lack of sleep decreases cortisol levels, which in turn can lower the testosterone levels. Hence, night shifts must be avoided if possible. Regularly working the night shift might put you at higher risk of infertility, possibly by affecting hormone production.

Stress

Stress, whether physical, emotional or biological, can reduce the potential of male fertility, but there is no general consensus on how to measure it objectively. Maintaining a work-life balance is greatly helpful in managing stress. Cutting back at work, reducing the amount of travelling done, not taking on any extra projects at home all help to tip the scales in favour of your health. Trying acupuncture, yoga, meditation, breathing, massages and other mind-body therapies also help.

Sexually Transmitted Infections (STIs)

Infections such as chlamydia and gonorrhoea are a leading cause of infertility for women.

Radiation

Lifestyle choices are decisions that any individual can make to aid a healthy living and indirectly promote fertility. These may be difficult to implement in one's life, but on considering their benefits, it is surely worth the effort.