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What to eat for each stage of your fertility journey

Knowing what to eat and when may seem a little daunting when on a fertility journey. Nutritionist Sophie Lester (RNutr) has everything you need to know.

It is good for men and women to know that you do not need to follow any special diet whilst on a fertility journey.

For the best chance at conceiving, experts recommend a healthy, well-balanced diet, but there are a few extra things to consider. Read on to find out more.

Aim for a balanced and varied diet.

To increase your chances of conceiving and support a healthy pregnancy, experts recommend you eat a balanced and varied diet that is rich in fruit and vegetables. You can find out more about the basis of a healthy diet here.

A fad or crash diet during your fertility journey should be avoided because it can increase the risk of missing essential nutrients which keep you and your reproductive fertility optimal. If pregnancy does occur, nutrient deficiencies can harm the baby’s development, so experts recommend that you stick to a varied and nutrient-rich diet, which follow healthy eating guidelines.

A well-balanced diet during your fertility journey could also help maintain a healthy weight and Body Mass Index (BMI). Both a low BMI (underweight) and a high BMI (overweight) are strongly linked to infertility in both men and women and the chances of carrying a healthy baby full term. Also, experts do not regularly recommend weight loss during pregnancy. This means that the time you are trying to conceive is the best time to start thinking about getting your BMI into the ideal range (between 18.5 and 24.9).

You can read how to measure your BMI here.

Do I need to eat more during pregnancy?

The common phrase that you’re ‘eating for two’ is a misconception. Only in the third trimester do you need extra calories – and only around 200 kcal more (about the same amount of calories in two bananas - or four biscuits). Though women underweight at the start of pregnancy, or those who maintain or increase their activity levels, may need more calories during pregnancy.

Weight gain during pregnancy is very individual, so there are currently no UK recommendations on how much weight you should gain. If you are concerned you are not gaining enough weight during pregnancy or gaining too much, it is recommended you speak to your doctor, dietitian or maternity team, who will be able to support or reassure you.

Important nutrients to find in foods for fertility and pregnancy:

Omega-3

You can find Omega-3 fats in oily fish and plant sources such as linseed, walnuts and chia seeds. In men, experts link the consumption of enough omega-3 through foods to better sperm quality [6]. Your requirements for omega-3 fats increase in pregnancy and lactation because the baby needs it for healthy eye and brain development [8]. Recommendations state that we eat two portions of oily fish a week. If you are pregnant, experts recommend you have no more than this because it can contain small amounts of chemicals which are harmful in excess. You should also avoid some supplements, such as cod liver oil (read more in final section).

Iodine

Iodine is essential for fertility because it maintains normal reproductive function. If pregnant, lactating or planning a pregnancy, your iodine requirements increase because it helps with a baby's growth [3]. The UK’s National Diet & Nutrition Survey (NDNS) found that women of childbearing age in the UK (16-49 years old) had average iodine levels more than 30% lower than the levels needed in pregnancy and lactation [9, 10, 14]. Iodine deficiency during pregnancy is associated with poor cognitive development in the child [9, 10]. Good food sources of iodine include fish, milk, cheese and eggs. Plant sources of iodine are highly variable, so vegans may want to look for fortified plant milk. Iodine supplements can be dangerous, so you should only take them under a doctor or dietician's advice and contain no more than 140 ug/day [4].

Folate

Folate is a form of 'folic acid' that occurs naturally in foods. Enough of this mineral is essential for healthy red blood cell and healthy nerve development in a growing baby [3]. Women who are planning to become pregnant, or are in the first 12 weeks of pregnancy, are currently recommended to eat foods rich in folate. They should also take a daily supplement of 400 ug of folic acid (see supplementation section below).

Here are some common food sources of folate in the UK diet:

Food source Folate per portion (ug)
85g Broccoli (steamed) 61
90g Spinach (boiled) 73
135g Baked beans 39
100g Chicken (roast) 10
150ml Orange juice 27
30g Fortified cereal (Cornflakes, Tesco) 120

 

Vitamin B12

Vitamin B12 is essential for making red blood cells and keeping the nervous system healthy. Experts link deficiencies of vitamin B12 to infertility [5]. You can only find vitamin B12 in animal products. Those who follow a vegan diet should eat foods fortified with vitamin B12 at least twice a day, such as fortified plant-based milk. The British Dietetic Association (BDA) recommends for those who do not think they are meeting their needs from foods consider taking a daily 10 ug supplement of Vitamin B12 [5]. You should always talk to your doctor or consult a dietitian before taking new supplements.

Nutritional supplements for fertility and pregnancy

Some nutrients are difficult to get enough of in a varied and balanced diet.

Vitamin D: Vitamin D is essential for growing and maintaining healthy bones. In general, food does not supply us with enough vitamin D to meet our needs, and we must obtain Vitamin D through sunlight. In wintertime, the sunlight we receive is poor, so experts recommend that everyone take a daily vitamin D supplement (10ug or 400 IU). This is especially important for women in pregnancy to ensure the development of healthy bones in your baby. Some women at higher risk may need to take vitamin D all year round, and some may need to take a slightly higher supplement (25 ug or 1000 IU) [3]. This includes women with darker skin tone, those who work indoors, and those who often cover their skin [3]. Folic acid: Women who are pregnant or planning to become pregnant need folic acid for a healthy brain, nerves and spinal cord in a growing foetus. The link between folic acid supplementation and a lower risk of neural tube defects (NTDs) is well known. NTDs affect 1 in 1,000 pregnancies every year [11].

The National Diet and Nutrition Survey (NDNS) revealed that 75% of women between 16 and 49 years in the UK have blood folate levels below the World Health Organisation cut-off for preventing NTDs [2].

Women who stop taking contraception and are sexually active, or trying for a baby, should take a folic acid supplement at a dose of 400ug/day. Women who become pregnant should continue to supplement 400ug/day of folic acid for the first 12 weeks of pregnancy. These women should also eat foods rich in folate (the natural form of folic acid in foods), such as green leafy vegetables (see food sources above). Some women may need a higher dose of folic acid (5mg) which you can buy on prescription. This is true if they have diabetes, obesity or coeliac disease and/or a history of NTU or are at higher risk of having babies with neural tube defects [8]. If you think this occurs to you, you should speak with your doctor, who will be able to assess your needs for a higher dosage. It is known that only a third of women take supplements before pregnancy, with the lowest uptakes in Afro-Caribbean women (17%) and those aged under 20 (6%) [2]. Many countries worldwide have introduced mandatory fortification of flour with folic acid, and the UK is currently debating whether they should do the same [1,2].

What about other supplements?

If you take any other supplements during pregnancy, such as a multivitamin, be sure to check that they don’t contain vitamin A. Some vitamin A (such as the small amount you get from foods) is essential for a healthy baby - but too much vitamin A is teratogenic (it can cause birth defects). Experts currently recommend you avoid supplements containing vitamin A in preconception and pregnancy [3].

Women who are vegan, and are concerned about their nutrient intake, may want to speak to a doctor or dietitian about additional supplements, such as vitamin B12, iodine, and omega-3 [3]. If you are thinking about taking new supplements, especially if you are pregnant, it is strongly advised you speak to your doctor beforehand. It is safer to find food sources of nutrients if you can because you are less likely to take too much.

Food safety in preconception and pregnancy

Both men and women should learn about the foods to avoid in preconception and pregnancy to avoid any risk to the mother and baby. Caffeine – Experts in the UK recommend that daily caffeine intake is limited to 200mg a day in pregnancy. This is equivalent to around two mugs of instant coffee or three cups of tea. But be aware that certain fizzy drinks such as cola and chocolate contain caffeine too – women should consume no more than five cans of cola and four bars of chocolate [8].

Alcohol – One large study has found that alcohol consumption is a risk factor for low semen volume in men [7]. It is known that alcohol can harm a developing foetus during pregnancy; this is especially true in early pregnancy. So, alcohol is best avoided completely preconceptually, both in both men and women, as well as during pregnancy.

Liver and liver products – Women who are planning to become pregnant or are pregnant should avoid these foods. These foods contain high vitamin A levels, which can be teratogenic (it can cause disabilities in the baby). Also, women should avoid supplements containing vitamin A or retinol (some multivitamins).

Raw meat and fish can contain bacteria that may harm women or the developing fetus, so ensure you cook all meat, fish, and poultry well, before serving.

Some cheeses – Soft cheeses such as brie and camembert, blue-vein cheese such as danish blue, unpasteurised milk and cheeses, can be harmful and best avoided in pregnancy.

Some types of fish – swordfish, marlin and shark contain high amounts of heavy metals such as mercury which can be harmful in excess. Limit oily fish to two times a week [8].


References

1. https://www.gov.uk/government/consultations/adding-folic-acid-to-flour/proposal-to-add-folic-acid-to-flour-consultation-document

2. https://www.bda.uk.com/resource/folic-acid-fortification-in-the-uk.html

3. https://www.bda.uk.com/resource/pregnancy-diet.html

4. https://www.bda.uk.com/resource/iodine.html

5. https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/complications/

6. https://doi.org/10.1093/hropen/hoy001

7. https://doi.org/10.1016/j.fertnstert.2010.06.031

8. Gandy, J. ed., 2019. Manual of dietetic practice. John Wiley & Sons.

9. https://www.bda.uk.com/resource/the-essential-role-of-iodine-in-the-diet.html?fbclid=IwAR3XFe-sUJ8iDhGzPijVW8K-IyYviTSTwWv69-IyIroX5JVCoYsjuqGYllI

10. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: Results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet [Internet]. 2013;382(9889):331–7. Available from: http://dx.doi.org/10.1016/S0140-6736(13)60436-5

11. Combet, E., Bouga, M., Pan, B., Lean, M.E.J. and Christopher, C.O., 2015. Iodine and pregnancy–a UK cross-sectional survey of dietary intake, knowledge and awareness. British journal of nutrition, 114(1), pp.108-117.

12. https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/

13. https://action.org.uk/research/preventing-neural-tube-defects

14. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699241/NDNS_results_years_7_and_8.pdf