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Preconception vitamins and supplements

Preconception health plays an important role in becoming pregnant, and providing the optimum environment for developing foetus, once pregnant. Maintaining a nutrient rich diet is the most effective way of ensuring your body is receiving all the appropriate nutrients during the preconception period.

Some supplements may be necessary in order to achieve the recommended nutritional uptake. This resource is intended to provide you with information about supplements commonly discussed in relation to sub-fertility and the preconception period.

Please consult your doctor about which supplements to take.

Recommended supplements based on Australian clinical guidelines:

Supplement: Folic acid

Who: All women in the preconception period and during early pregnancy should take folic acid

Dose: 400-500µg at least 4 weeks prior to conception and for first 12 weeks of pregnancy. Women who are taking anticonvulsant medication, have BMI >30, have malabsorption issues may be required to take a higher dose.

Evidence: Taking folic acid prior to and in the early stages of pregnancy reduces the risk of neural tube defects such as spina-bifida.

Supplement: Iodine

Who: All pregnant people

Dose: 150µg daily while pregnancy and breastfeeding

Evidence: Important for the production of the maternal thyroid hormone, foetal brain and central nervous system development

Supplement: Vitamin D

Who: People with a vitamin D deficient (identified with a blood test)

Dose: 1000 IU/day (vitamin D 30–49 nmol/L) or 2000 IU/day (vitamin D <30 nmol/L)

Evidence: Reduces impaired skeletal development and small for gestational age babies

Supplement: Iron

Who: People with iron deficiency (identified by blood tests)

Dose: As directed by doctor

Evidence: Prevents anaemia


Supplement: Vitamin B12

Who: Vegans and vegetarians

Dose: As directed by doctor

Evidence: Important for neurological development of the infant


Preconception and pregnancy supplements have not been proven to improve fertility and pregnancy outcomes. Therefore it is recommended that women take micronutrients that are specific to their needs and maintain a healthy diet with a wide variety of foods with the aim of achieving the optimal nutritional intake. Some micronutrients in multivitamins compete for absorption in the body and some multivitamins do not contain the recommended amounts of folic acid and iodine and therefore additional supplements may be required.

Additional supplements

In recent times, many studies have been conducted to find strategies, drugs, or compounds such as antioxidant drugs and supplementation with vitamins or hormones that may improve oocyte, sperm and embryo quality and therefore improve fertility outcomes. These supplements have varying levels of evidence to support their efficacy. Below is a brief overview of the theories underlying some of the more commonly utilised supplements.


When deciding whether to take the below supplements, it is important to be aware that the evidence for improving outcomes is limited, and supplements may be costly and may have side effects. You must speak to your fertility specialist for advice when considering these supplements.

Coenzyme Q10 / Ubiquinol

Oxidative stress plays a role in sub-fertility by impacting egg quality. Antioxidants are compounds made in the body that help to mitigate oxidative stress. Coenzyme Q10 (CoQ10) is an antioxidant made endogenously by the body, and is also made synthetically, in the form of over-the-counter supplements. CoQ10 supplements, also known as Ubiquinol is sometimes administered in the fertility context with the understanding it may reduce oxidative stress and therefore prevent the deterioration of egg quality. Current research suggests that it may increase clinical pregnancy rates but there are no high quality studies that suggest CoQ10/Ubiquinol supplements improve live birth rate.


Recently, studies on inositol supplementation during IVF have gained particular importance due to the effect of this molecule on reducing insulin resistance, improving ovarian function, egg quality and embryo and pregnancy rates and reducing gonadotropin amount during stimulation. Inositol and its isoform, especially myo-inositol (MI), find their application as pre-stimulation therapy in polycystic ovary syndrome (PCOS), patients undergoing IVF cycle and, recently, also in other sub-fertile patients such as poor responders. Again, some studies have demonstrated increased clinical pregnancy rates but none are yet to confirm increased live birth rates.


Oxidative stress can play a role in infertility by impacting egg quality and therefore reducing the maturation of eggs and fertilisation rates. There is some evidence to suggest that melatonin supplements may help to further neutralise oxidative stress. Some studies suggest that melatonin significantly increases the clinical pregnancy rates in assisted reproductive technology (ART) cycles. It also suggests a link between melatonin levels and an increase in the number of eggs collected, the number of mature eggs collected and the number of good quality embryos formed. Similarly, there is no clinically significant evidence to suggest that melatonin increases live birth rate - further large scale studies are required to confirm this.



DHEA is a type of steroid hormone made in the adrenal glands and gives rise to the male and female sex hormones, testosterone and oestrogen. Oestrogen is the hormone responsible for the growth of oocytes in the ovaries. As women age, their oestrogen levels decrease and there is some evidence to suggest that DHEA supplementation may increase these levels. DHEA supplementation may improve follicular sensitivity to follicle stimulating hormone (FSH) and therefore improve response to ovarian stimulation in IVF/ICSI as well as improve oocyte quality. Women who have high FSH levels and low anti-mullerian hormone (AMH) levels undergoing IVF/ICSI may benefit from the use of DHEA. It is typically recommended to those who have previously responded poorly to FSH due to low ovarian reserve.

Restrict - nutrients/substances to restrict based on Australian clinical guidelines:

Supplement: Vitamin A

Who: Women in the preconception period and pregnant women

Dose: Dietary sources do not pose a risk however vitamin A supplements should be limited to 3000IU per day. Synthetic retinols should be ceased one month prior to conception.

Evidence: Increased risk of miscarriage and CNS malformations


Nutrient: Mercury containing fish

Who: Women in the preconception period and pregnant women

Dose: Limit of one serve per fortnight of fish containing high levels of mercury (shark, billfish) and no other fish to be eaten in that period, or avoid fish containing high levels of mercury and eat two to three serves of other types of fish per week

Evidence: Increased risk of negative effects on foetal brain and central nervous system

Substance: Caffeine

Who: Women in the preconception period and pregnant women

Dose: Limit to 300 mg or less per day (equivalent to two to three standard cups of coffee)

Evidence: Increased risk of foetal growth restriction

Substance: Alcohol

Who: All women who are pregnancy or trying to conceive

Dose: There is no established ‘safe dose’ of alcohol during pregnancy and when trying to conceive and therefore abstinence is recommended.

Evidence: It is not clear what effect drinking small amounts of alcohol can have on unborn babies but it is well known that high alcohol consumption can be harmful.

While it is not known exactly how alcohol affects fertility in women, research shows that even drinking lightly can increase the time it takes to get pregnant, and reduce the chances of having a healthy baby.

Substance: Smoking

Who: All women who are pregnancy or trying to conceive

Dose: There is no safe limit of smoking

Evidence: Men and women who smoke are more likely to have fertility problems and take longer to conceive than non-smokers. Women who smoke in pregnancy are more likely than non-smokers to experience miscarriage and their babies have increased risk of low birth weight, being born prematurely and having birth defects.


Dorney, E., & Black, K. (2018). Preconception Care. Australian Journal of General Practice, 47(7), 424-429.

Florou, P., Anagnostis, P., Theocharis, P., Chourdakis, M., & Goulis, D. (2020). Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? A systematic review and meta-analysis of randomized-controlled trials. Journal of Assisted Reproduction and Genetics, 37, 2377-2387.

RANZCOG. (2022, May 4). Dietary supplements in pregnancy. Retrieved from RANZCOG:

Your Fertility. (2022, June 30). Your fertility. Retrieved from Healthy eating and exercise:

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