The role of nutrition during preconception and pregnancy

Planning a pregnancy is both an exciting and important time. It is always preferable for both mother and father to assess their health and nutrition before conceiving a child; which will optimise the chances of conception, wellbeing in pregnancy and the health of the baby.

Unfortunately, conceiving and giving birth to a healthy baby can sometimes be a challenge. According to the NHS, around one in seven couples may have difficulty conceiving – approximately 3.5 million people in the UK.1 Often there is no clear causative factor leading to infertility or subfertility and infertility is frequently labelled as ‘unexplained’. Although this can be frustrating, it does mean that if wellbeing is optimised, the chances of conception and a healthy pregnancy may improve.

In couples who do not suspect or have not been diagnosed with infertility, it is still advisable for both the mother and father to optimise their own health before conceiving in order to support a healthy conception and pregnancy.

In this week’s blog, we will discuss the causes of infertility and the importance of nutrition during preconception and pregnancy.

Skip to Key Takeaways

What is infertility or subfertility and how is it diagnosed?

The World Health Organization defines infertility as failure to achieve a clinical pregnancy after twelve months or more of regular unprotected sexual intercourse with the same partner (specified as on average twice per week) and can be diagnosed after this period of time.1  Male infertility may additionally be diagnosed by sperm abnormalities confirmed by two analyses of sperm count, morphology, motility or other aspects.2

Approximately 80% of couples will conceive within the first year; half of the remaining 20% will conceive within the second year. Infertility occurs in 5-10% of couples and it is accepted that one third is due to female causes, one third male causes and one-third combined causes.3 Subfertility is similar to infertility, however, with subfertility there is no specific reason why a pregnancy cannot occur and therefore optimising health has the potential to allow a successful pregnancy.

What causes infertility or subfertility?

Low fertility can be due to many factors, however, it is often considered by health professionals to be idiopathic, meaning there is no known cause.

Female reproductive conditions such as blocked fallopian tubes, polycystic ovary syndrome (PCOS), endometriosis, fibroids, hyperprolactinemia, anovulation and other hormone imbalances can contribute to, or cause, infertility.

Male infertility can be due to poor sperm count or quality e.g. low motility or abnormal morphology. There are many factors which can directly affect sperm quality or interfere with hormone signalling which controls sperm production.

Interruption to hormonal control, which affects the ability to produce adequate sperm, ovulate or maintain pregnancy, can be influenced by a number of factors, including:

  • Stress and adrenal dysfunction – cortisol inhibits the release of gonadotrophin releasing hormone (GnRH) and therefore can suppress ovulation or spermatogenesis (sperm production) as well as sexual activity. Adrenaline can also inhibit the utilisation of progesterone, therefore disrupting hormonal control of the female reproductive system. Cortisol and the sex hormones are synthesised from pregnenolone therefore excess production of cortisol has the ability to deplete production of other steroid hormones – sometimes referred to as ‘the pregnenolone steal’.4 Some studies have now also identified that stress increases the newly discovered gonadotrophin inhibiting hormone (GnIH)5 which will prevent the production of hormones responsible for ovulation and spermatogenesis (luteinising hormone, LH and follicle stimulating hormone, FSH). So if excess stress or adrenal dysfunction is suspected, stress management techniques and adrenal support should be put in place5,6
  • Low thyroid function – hypothyroidism is associated with low fertility, particularly in females, therefore thyroid conditions or sub-clinical hypothyroidism should be investigated and supported if fertility is reduced7
  • Poor gut and liver function – the liver and gut are responsible for the metabolism and elimination of oestrogen. If the gut is not working efficiently, oestrogen, which should be excreted, can be reabsorbed into the body (particularly in cases of constipation). The liver is responsible for detoxifying waste oestrogen to allow it to be excreted. Therefore inadequate liver and/or digestive function can lead to a higher ratio of oestrogen to progesterone, known as oestrogen dominance, which has been shown to have a negative effect on fertility and also increase the risk of conditions such as endometriosis and PMS. Therefore the health of the gut and liver should be considered when supporting fertility8
  • Weight – a low BMI (under 19) or less than 17% body fat, can result in anovulation (absence of ovulation). A BMI of over 30 can also interfere with ovulation and spermatogenesis (obese men have up to 50% fewer sperm), increased risk of miscarriage and reduce IVF success. The optimum fat percentage for fertility is 20-25% (this is also a healthy BMI)2,9
  • Age – after the age of 35 female fertility begins to reduce, although this is not a modifiable factor it is advisable that women over 35, who have been attempting to conceive for over a year, should seek potential investigations or interventions to optimise chances of conception2

Other factors which affect fertility in both men and women are:

  • Mitochondrial function – energy production by the mitochondria is essential for normal sperm production, morphology and motility. It is also essential for the normal production of an oocyte (egg) by the mother10-13
  • Oxidative stress – affects sperm quantity and quality as it can damage:
  1. The mitochondria of the spermatogonium (sperm-producing cells) which will directly affect adequate sperm production
  2. The sperm, particularly the cell membranes which are so important for the function of each sperm

In women, if the cell membrane of the oocyte is exposed to oxidative stress, it can be more difficult for the spermatozoa to penetrate it.3,14

Other factors associated with poor fertility which should be addressed, if relevant:2

  • Irregular sleep patterns
  • Smoking
  • Alcohol
  • Environmental toxins
  • Marijuana
  • Caffeine

Dietary recommendations

Preconception is an important time, during which both prospective parents can prepare their bodies by ensuring good nutrition to assist fertility and conception. Once conception has occurred, then continuing with a high quality, nutrient dense diet and balanced lifestyle can support the health of both mother and baby.

Dietary recommendations for fertility are aimed at supporting healthy hormone, oocyte and sperm production as well as mitochondrial function which is required for DNA replication and cell (oocyte or sperm) formation. Dietary characteristics associated with optimal fertility include:2

Avoid/Reduce Increase
Trans fatty acids (found in heavily processed and baked goods) Healthy fats including omega-3 and mono-unsaturated fat
Excessive intake of animal protein High intake of fibre from vegetables, fruits and some wholegrains (those that are naturally gluten-free)
Gluten – this should be considered  as subfertility is seen in individuals with coeliac disease and non-coeliac gluten sensitivity Intake of vegetable protein
High glycaemic load carbohydrates (e.g. white bread, pasta and rice) and sugar

Specific Nutrients to support Female Fertility and Pregnancy

Optimising cell membrane and mitochondrial function, hormone balance, methylation and reduction of oxidative stress as appropriate.

Essential fatty acids: The cell membrane surrounding the oocyte is important for overall oocyte development and also for allowing the sperm to penetrate it. Therefore cell membrane health should be supported.15,16

Omega-3 fats are incorporated into the cell membrane aiding membrane fluidity and assisting oocyte penetration. EFAs are also associated with supporting normal hormone production, mitochondrial and adrenal function. DHA (an omega-3 fatty acid found in oily fish) is particularly important for cognitive and visual development of the growing foetus.

A Cochrane review published in 2018 concluded that increasing omega-3 LCPUFA intake during pregnancy, either through supplements or in foods, may reduce the incidence of preterm birth (before 37 weeks and before 34 weeks) and there may be less chance of having a baby with a low birthweight. Women who take omega-3 LCPUFA supplements during pregnancy may also be more likely to have longer pregnancies

Alpha lipoic acid: Powerful antioxidant which also regenerates vitamin C, vitamin E, CoQ10 and glutathione.17 However, safety has not been established in pregnancy, therefore any supplements should be stopped prior to conception.

Vitamin A: Antioxidant that also has an important role in cellular growth and differentiation and is required for embryonic development.18 Caution is needed with supplementation in pregnancy as high vitamin A intakes have been associated with congenital abnormalities.

B vitamins: Many of the B vitamins are involved in cellular replication, DNA and hormone production as well as mitochondrial energy production. For example, folate is required for DNA and RNA synthesis and methylation and is associated with a reduced risk of neural tube defects – the government recommends supplementing 400µg for at least 3 months prior to conception and during the first trimester.

Vitamin C: Antioxidant that has the ability to regenerate glutathione. It has further effects on reproductive health as it has a positive effect on growth and repair of the ovarian follicle and the development of the corpus luteum (essential for maintaining a pregnancy). Vitamin C is also associated with a reduced risk of preeclampsia.19,20

Vitamin E: A fat-soluble antioxidant which is important for maintaining ovarian health.12

Selenium: Supports thyroid hormone production (as mentioned earlier suboptimal thyroid function is associated with low fertility), it is also a powerful antioxidant and involved in glutathione regeneration.21

Zinc: A cofactor for enzymes which are involved in the production of DNA and RNA, protein synthesis as well as protecting against oxidative damage. Zinc also plays an essential role in the production and transport of reproductive hormones and enables ovulation, fertilisation and oocyte development.21-23

Flavonoids and carotenoids: Possess antioxidant as well as anti-inflammatory capabilities. Some additionally act as polyphenols which can be considered prebiotics, supporting the microbiota.24,25

Consideration should also be given to vitamin D, iodine and iron which all have important roles both preconceptually and during pregnancy.

Supporting Gut Health

The mother’s gut flora play an essential role in fertility, pregnancy and the health of the baby. A balanced gut microbiota has been shown to protect against atopic conditions such as allergy, eczema and asthma in the baby. It is also essential for the development of the baby’s immune system. Therefore using a live bacteria supplement to support the balance of the microflora within the mother’s gut is recommended.26-30

And finally, this healthy regime is essential in the period of breastfeeding and beyond to support growth in the baby and to meet the demands and recovery placed on the mother.

Key Takeaways

• Infertility occurs in 5-10% of couples and it is accepted that one third is due to female causes, one third male causes and one third combined causes2,3
• Subfertility is similar to infertility, however, with subfertility there is no specific reason why a pregnancy cannot occur and therefore optimising health has the potential to allow a successful pregnancy
• Factors which can affect both male and female fertility include: stress, irregular sleep patterns, smoking, alcohol consumption, environmental toxins, caffeine and recreational drugs such as marijuana and food sensitivities (including non-coeliac gluten sensitivity)
• Interruption to hormonal control, which affects the ability to produce adequate sperm, ovulate or maintain pregnancy, can be influenced by a number of factors, including adrenal and thyroid function, gut and liver health, mitochondrial function and oxidative stress
• Preconception is an important time, during which both prospective parents can prepare their bodies by ensuring good nutrition to assist fertility and conception. An anti-inflammatory diet is associated with optimal fertility (lots of vegetables, healthy fats, low in sugar and inflammatory fats)
• Specific nutrients to support female fertility and pregnancy include: essential fatty acids, antioxidants, B vitamins and vitamin D and trace minerals. The government recommends vitamin D and folate are taken for three months pre-conceptually. We would recommend an all-round good quality multivitamin and mineral that includes folate and vitamin D, plus other nutrients and that has been formulated specifically for pregnancy.

If you have any questions regarding the topics that have been raised, or any other health matters please do contact me (Helen) by phone or email at any time., 01684 310099

Helen Drake and the Cytoplan Editorial Team

Relevant Cytoplan products

Pregna-PlanA comprehensive multivitamin and mineral suitable for preconception, pregnancy and breastfeeding. Two tablets contain the full range of B vitamins including 400ug; methylfolate, (folic acid) essential for nerve and cognitive development and for the prevention of spina bifida.

Omega 3 Vegan – An omega-3 supplement isolated from algae providing a higher ratio of DHA to EPA than that of fish oils. DHA is an important fatty acid for cognitive and visual development.

Acidophilus Plus – A live bacteria supplement containing 8 strains of bacteria as well as 35mg of fructo-oligosaccharides (FOS), in capsule form.

Vitamin D3 – 62.5ug (2500IU) and also as drops which can be added to water, 2 drops = 5ug (200IU)

Methylfolate (400ug) – Folate in the active form as methylfolate. In specific cases where there is a high risk of neural tube defects the G.P. may recommend additional methylfolate

Phytoshield – Phytonutrient and antioxidant supplement containing a variety of flavonoids and carotenoids. Can be used in the preconception period

Cyto-Renew – Phytonutrient and antioxidant complex including CoQ10 and alpha lipoic acid. Can be used in the preconception period.


  2. Murray, M. and Pizzorno, J. (2013) Textbook of Natural Medicine, 4th Ed.
  4. Wagenmaker, E. R. et al. (2009) ‘Psychosocial Stress Inhibits Amplitude of Gonadotropin-Releasing Hormone Pulses Independent of Cortisol Action on the Type II Glucocorticoid Receptor’, Endocrinology, 150(2), pp762–769.
  5. Kirby, E.D. et al. (2009) ‘Stress Increases Putative Gonadotropin Inhibitory Hormone and Decreases Luteinizing Hormone in Male Rats’, Proceedings of the National Academy of Sciences of the United States of America, 106(27), pp11324–11329.
  7. Poppe, K. et al (2004) ‘Thyroid Dysfunction and Autoimmunity in Infertile Women’, Thyroid, 12(11), pp997-1001.
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  11. Cassina, A. et al. (2015) ‘Defective Human Sperm Cells Are Associated with Mitochondrial Dysfunction and Oxidant Production’, Biology of Reproduction, 95(5), 119 pp1–10
  12. Amaral, A. et al. (2013) ‘Mitochondria functionality and sperm quality’, Reproduction 146(5) pp163-74.
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  19. Luck, M.R. et al. (1995) ‘Ascorbic Acid and Fertility. Biol’, Reprod, 52(2), pp262-266.
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4 thoughts on “The role of nutrition during preconception and pregnancy

  1. Why have you not cited the recent Cochrane review on Omega-3 for pregnancy? – there is evidence it reduces the risk of premature birth

    1. Hi Elizabeth,
      Thank you for pointing out this omission. As you know this review was published in October 2018 and concluded that:
      “Increasing omega-3 LCPUFA intake during pregnancy, either through supplements or in foods, may reduce the incidence of preterm birth (before 37 weeks and before 34 weeks) and there may be less chance of having a baby with a low birth weight. Women who take omega-3 LCPUFA supplements during pregnancy may also be more likely to have longer pregnancies”
      We will add this to the blog.
      Best wishes,

  2. Very informative! That is why I take probiotics regularly especially when I was pregnant. It helps me overcome my mastitis during breastfeeding and at the same time protect my baby from various illness particularly skin diseases. Thanks for the info. 🙂

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