The impact of health behaviour on fertility

Did you know that diet, exercise, weight, smoking and alcohol affect fertility? Learn more about them here.


There is growing evidence that lifestyle matters a lot, not only for the health of the newborn baby, but also for health later in life.

Nutrition can have an effect on fertility. Higher blood sugar levels and/or insulin can affect reproductive hormones and these, in turn, can affect ovulation and fertility. 

If you want to get pregnant, it is recommended to maintain a healthy diet. A healthy diet contains all the necessary proteins, fibre, fats, vitamins and minerals. A balanced diet can help you to get pregnant more easily. It provides the necessary vitamins and minerals, and it is becoming more and more clear that certain vitamins and minerals affect egg and sperm quality. So if there is one period in your life where a healthy and balanced diet is of importance, it is now and during pregnancy. You don't need to eat more during pregnancy.  There is a slightly higher energy requirement, especially in the third trimester, but most women also move less when pregnant, so the higher need is already compensated by reduced energy consumption.

In the first trimester of pregnancy, you may feel less nauseous if you eat something from time to time. At these times, try to choose healthy snacks and not 'empty calories'; these are snacks that are high in calories but have little nutritional value, e.g. biscuits, chocolate, soft drinks. It is better to choose healthy snacks such as a whole-grain rusk, carrots, fruit, yoghurt or a handful of nuts.

Prefer not to eat: Preferred:
Chocolate Fruit
Candy Snack vegetables such as carrots, tomatoes, cucumber
Biscuits with sugar or salt wholemeal biscuits
Sodas Yoghurt
  Nuts without sugar or salt


You can already take these hunger moments into account when shopping and make sure you have healthy snacks at home. You can also pack some in your lunch bag for work, to avoid a visti to the snack machine with (usually) unhealthy alternatives. Also make sure you have some ingredients available to prepare a healthy meal. This is a better alternative than a frozen pizza or ready-made lasagne.


Both obesity and underweight affect fertility and success rates of fertility treatments, both in women and men. This is because body fat affects sex hormones. Given that it is not advisable to lose weight during pregnancy, it is best to aim for a healthy weight before pregnancy.

With an elevated BMI, it may take longer to get pregnant. With a BMI of 30 or higher, the chances of a successful pregnancy decrease by 4% per BMI point increase. If you also smoke, for example, the chances of pregnancy drop further.

Losing 10% of your weight can boost your fertility. If you are overweight, your hormone balance is disturbed and this affects ovulation. Losing weight is not easy, so it is advisable to seek help from a dietician. With this guidance, you can lose weight in a healthy way.

Some tips for eating healthy portions:

  • Put only the food you want to eat on the table (e.g. fill the number of sandwiches you want to eat in advance and put only these filled sandwiches on the table)
  • Do not prepare too large of portions. If you have any leftovers, save them hygienically for another time or freeze a portion. A lot of food is thrown away and it is good to act against this waste. Listen to your sense of hunger though, are you no longer hungry? Then prefer not to eat the leftovers.
  • Scoop the portion you are allowed to eat onto your plate and try to resist the urge to take a second portion
  • Make sure you have healthy snacks at home (yoghurt, nuts, wholemeal biscuits, fruit, vegetables)
  • Do nothing but eating (and talking to your tablemates) during the meal. Scrolling or reading will make you eat more.
  • Consider omitting sauces at dinner. This can easily save 100 kcal per meal.
  • Drink a large glass of water before eating. This reduces the feeling of hunger. You can also do this during the day if you feel hungry. This will also help you reach the recommended daily fluid intake.

It is best to start losing weight early enough (4 to 6 months before you get pregnant). 



Certain substances in our environment affect fertility.

Click here if you want to know more about these substances.

Physical activity

Regular exercise does not only impact your general health and mental health positively, it is also beneficial for fertility.

It is recommended to have between 2.5 hours and 5 hours (or 150 minutes to 300 minutes) of exercise (walking, cycling, physical work) and 1.5 hours (or 75 minutes) of sport per week. Exercise can be spread out over the week, for example, walking for half an hour daily or walking around the block twice a day. If you leave your car at home more often or park further away, take the stairs instead of the lift more often or stand up every hour to refill your water bottle, you will already be closer to achieving your exercise goals.

You can also exercise during pregnancy, as long as it doesn't bother you and there is no risk for abdominal trauma. For this reason, combat sports, for example, are not recommended; cycling and swimming can usually be continued.

Smoking, alcohol and drugs

When you quit smoking, you have a greater chance of getting pregnant; fertility treatment is also more successful when both partners do not smoke. Furthermore, quitting smoking reduces the risk of miscarriage.

It's best to quit smoking as soon as possible, ideally as soon as you start thinking about becoming pregnant. For example, it takes three months for the harmful effects of smoking on sperm quality to disappear in men. Women who quit smoking before pregnancy have babies with a similar birth weight to those who never smoked. If you quit smoking before pregnancy, you also don't have a higher risk of having a child with a birth defect. Completely quitting has many more benefits than just reducing the number of cigarettes.

If you were unable to quit smoking before pregnancy, stopping during pregnancy is still strongly recommended. Quitting smoking at any point during pregnancy has benefits. It can reduce various health risks for the child, such as those related to congenital conditions. You can receive support and guidance from a tobacco specialist. A tobacco specialist is a doctor, psychologist, or another healthcare professional (midwife, physiotherapist, nurse, etc.) who has received additional training in tobacco cessation. A tobacco specialist assists you with the quit-smoking process by collaboratively determining a personalized cessation plan and using aids to support you. They help you manage feelings of guilt or stressful factors that trigger smoking.

Alcohol affects fertility in both men and women. The more and the more frequently one drinks, the lower the chances of getting pregnant. Fertility treatments are also less effective when alcohol is consumed.

Drugs likely impact fertility, but drug use is often associated with other harmful lifestyle factors, making it difficult to determine the specific effects caused solely by drugs themselves.

Unsafe sex

Sexually transmitted infections (STIs) can be a cause of fertility issues. As the term suggests, you acquire an STI through vaginal, oral, or anal sex with an infected person. Some STIs can be cured by taking antibiotics. Others are caused by a virus and are lifelong; this is the case for human papillomavirus, herpes simplex virus, hepatitis B, and human immunodeficiency virus (HIV). Fortunately, these viruses can also be managed today with medication. Prevention is always better than cure, and prevention is of paramount importance with STIs. You can do this by using a condom over the penis and using a dental dam for oral sex. Vaccines exist for hepatitis B and human papillomavirus.

It's not at all strange to ask a general practitioner for an STI test if you've ever had unprotected sex. On the contrary, you're showing that you're taking responsibility for another person. Testing for an STI can be quite simple, using a urine test, a swab, or a blood test. Definitely get tested if you experience symptoms such as pain while urinating or if you notice unusual discharge from the vagina or penis.

Sometimes there are no symptoms with an STI (for example, chlamydia), which actually makes it riskier to unintentionally transmit it to others. STIs can impact fertility, and many can be passed from a pregnant person to their baby, leading to serious health problems for the baby. Half of the women infected with chlamydia develop pelvic inflammatory disease (PID), an inflammation of the pelvic organs that can lead to permanent scarring of the fallopian tubes and infertility as a consequence.


Sleep affects our hormone balance and blood sugar levels.

Stress, mental issues, caffeine, alcohol, an unsuitable sleep environment, and the use of a computer or laptop before bedtime can negatively impact sleep. Engaging in sufficient physical activity during the day (not right before bedtime), especially outdoors, has a positive influence on sleep. Try to avoid factors that have a negative impact on sleep as much as possible and aim to go to bed on time.


The words "woman" and "man" are increasingly ambiguous concepts and should be avoided where possible. For ease of communication on this platform, we use the terms "woman" and "man" when providing information about biological processes. In this context, the term "woman" refers to a person with "female" sex characteristics (e.g., vulva, uterus, ovaries, etc.), and the term "man" refers to a person with "male" sex characteristics (e.g., penis, testes), although we are aware that:

1) There are many intersex individuals or individuals with variations in sex characteristics;

2) There are many people for whom gender identity does not fully correspond to or align with sex characteristics.

When providing information about relational aspects, however, the term "woman" does not refer to biological characteristics, but rather to gender. This also includes trans women (individuals who were legally registered as male at birth based on sex characteristics but have a female gender identity) and intersex individuals (born with variations in sex characteristics) who identify as women. Similarly, the term "man" refers to gender in this context, including trans men and intersex individuals who identify as men.