How Lifestyle Affects Fertility - Matt Prior `
Dr Matthew Prior

Matt Prior

How Lifestyle Affects Fertility

When trying to conceive it is important to prepare your body for pregnancy. Positive lifestyle changes will not only ensure the best start in life for your baby, but also improve the chances of getting pregnant.

Yes, this covers the usual medical mantra, stop smoking, lose weight and lay off the booze. But in this article I examine the evidence behind this advice by reviewing the impact of each different lifestyle factor.


Women with a low body weight take on average four times as long to get pregnant. They may find their periods come less often and may even stop having periods all together. Having regular periods is a good sign of ovulation and releasing an egg is essential to getting pregnant naturally.

Overweight women also take longer to conceive. Time to conception increases the more overweight, or obese a woman is. Weight loss in this situation has been shown to improve fertility.

The exact reason why being overweight reduces fertility is not properly understood. Theories include that more body fat alters hormones levels which affect ovulation and implantation.

We all come in different shapes and sizes, and this needs to be considered when assessing weight. Doctors assess weight using body mass index (BMI) calculated based on weight and height.

A normal body mass index is between 18.5 and 29.9, shown in the table. A BMI over 30 is classified as obese. Fertility treatment is not recommended for obese women as it is less effective and there are increased health risks of pregnancy.

BMI Category Effect on fertility
Below 18.5 Underweight May stop ovulation
18.5-24.9 Normal Positive effect
25.0–29.9 Pre-obesity Reduced
Over 30.0 Obesity Reduced

How to lose weight

Let’s not pretend weight loss is easy. The only way to manage weight is through a combination of diet and exercise.

Modifying diet is more effective, and losing weight through exercise alone is very difficult. Cut out snacks and refined carbohydrates such as sugar, fruit juice and white rice. Replace with complex carbohydrates like brown rice and cereals. A food diary can help, and set realistic targets. Joining a slimming or weight loss group can really help keep you motivated.


Health organisations recommend 30 minutes of exercise five times a week for everyone. Keeping active has positive effects on physical and mental health and help fertility. Exercise doesn’t have to mean going to the gym. Anything that increases your heart rate and makes you a little bit sweaty is enough to be considered exercise.


Women who smoke are more likely to have fertility problems than those who don’t. Smoking stops the ovaries working as effectively, damages eggs and alters hormone levels. Smoking may also stop the fallopian tubes from properly collecting an egg and transporting the embryo to the womb.

Little research has been done on the effects of vaping and fertility, so the advice for women trying to conceive is to avoid.


Heavy drinking has a negative effect on fertility. This again is likely due to effects on hormone levels. Alcohol can also cause harm to the developing baby. The safest approach for pregnant women or those trying to conceive is not to drink alcohol at all, to keep risks to your baby to a minimum.


Women who drink an excessive amount of caffeine, more than 500mg a day, have reduced fertility. This is a lot of coffee, equivalent to 5 brewed cups of coffee a day, or 10 espresso shots. Rest assured moderate caffeine intake has no impact on fertility.

Everything adds up

A combination of negative lifestyle factors results in a cumulative increase the time it takes to get pregnant.

Negative lifestyle risk factors include: women smoking 15 cigarettes a day, men smoking 15 cigarettes a day, men drinking more alcohol than 20 units per week, women drinking coffee or tea more than 7 cups a day, women’s weight over 70 kg or social deprivation.

Preparing for pregnancy

In addition to addressing lifestyle factors make sure you’re pregnancy ready.

Pre-natal vitamins

National guidelines recommend that women trying to conceive should take folic acid and vitamin D. These can be found in most over the counter pre-conception vitamins. Folic acid prevents a condition called spina bifida and vitamin D has been shown to be helpful in pregnancy.

Rubella vaccination

Getting rubella, otherwise known as German measles, during pregnancy can damage a baby’s development. Therefore make sure you’re immune before trying to conceive.

Smear Tests

Smears can’t be taken during pregnancy, so make sure you’re up to date.


Get ready for pregnancy and improve your fertility by addressing negative lifestyle factors. You really can make a difference.

This article was also posted on All About Fertility

May 10, 2020 | @DrMattPrior