Folic Acid and Fertility: The Vital Role of Vitamin B9 in Reproductive Health

Funmi Akinola (Msc, Anutr) Women and Health Mar 5, 2025

Fertility is a deeply personal and often complex journey for many individuals and couples. While numerous factors influence the ability to conceive, nutrition plays a crucial role in optimising reproductive health. Among the essential nutrients for fertility, folic acid stands out as a key player. Best known for its role in preventing neural tube defects in early pregnancy, folic acid is also integral to egg quality, and overall reproductive function.

Folic acid, a synthetic form of folate (vitamin B9), is an essential nutrient that plays a fundamental role in cell growth, DNA formation, and red blood cell production. While its significance in pregnancy is widely recognised, particularly in the prevention of neural tube defects, folic acid also has a crucial impact on fertility. Ensuring adequate folic acid intake before conception can enhance reproductive health, support egg maturation, and create optimal conditions for a healthy pregnancy. This article explores the role of folic acid in fertility, its sources, recommended intake, and the potential consequences of deficiency.

Understanding Folic Acid and Its Role in the Body

Folic acid is the synthetic form of folate, the naturally occurring version of vitamin B9 found in food. It is water-soluble, meaning it dissolves in water and is not stored in large amounts in the body. This necessitates regular dietary intake to meet the body’s needs.

One of folic acid’s primary roles is supporting DNA synthesis and cell division, which is particularly important for rapidly dividing cells, such as those involved in reproduction. Alongside vitamin B12, folic acid is essential in forming red blood cells and maintaining proper nerve function. Deficiency can lead to macrocytic anaemia, where red blood cells become enlarged and less effective at transporting oxygen throughout the body. Since oxygenation is critical for reproductive health, maintaining adequate folic acid levels is particularly beneficial for those trying to conceive.

Folic Acid and Female Fertility

Folic acid plays a significant role in female fertility by supporting regular ovulation and improving the chances of conception. Here’s how it influences reproductive health:

Egg Quality and Ovulation

Folic acid is involved in the maturation of oocytes (egg cells). Research suggests that women with sufficient folic acid levels are more likely to have regular ovulation cycles, which is key for conception. Poor ovulation is a common cause of infertility, and ensuring adequate folic acid intake may help prevent irregularities.

Neural Tube Defect Prevention

The importance of folic acid in pregnancy is well established, but its role begins even before conception. The neural tube, which develops into the baby’s brain and spinal cord, forms in the first few weeks of pregnancy, often before a woman knows she is expecting. Sufficient folic acid intake before and during early pregnancy significantly reduces the risk of neural tube defects such as spina bifida (improper development of the baby’s spine and spinal cord) and anencephaly (a birth defect where a baby is without the brain and skull).

Hormonal Balance and Cell Function

Folic acid contributes to hormone regulation, particularly in relation to oestrogen and progesterone, which are critical for a healthy menstrual cycle. It also supports the repair and maintenance of reproductive tissues, ensuring the uterus is in an optimal state for implantation.

Reduced Risk of Miscarriage

Some studies suggest that women with low folate levels may be at a higher risk of miscarriage. Although the exact mechanisms are still being explored, it is believed that folic acid’s role in DNA synthesis and cell division supports healthy embryo development and implantation.

How Much Folate and Folic Acid Do You Need?

The recommended daily intake of folate and folic acid varies depending on age, sex, and reproductive status:

Adults and children over 11 years: 200 micrograms per day
Women trying to conceive: 200 micrograms plus a 400-microgram folic acid supplement daily (ideally 12 weeks before conception)
Pregnant women: 300 micrograms plus a 400-microgram folic acid supplement daily for the first 12 weeks of pregnancy
Breastfeeding women: 260 micrograms per day

Some individuals, including those with a history of neural tube defects, diabetes, obesity, or those taking anti-epileptic medications, may need higher doses (5 milligrams daily), as prescribed by a healthcare professional.

Methyl Folate and the MTHFR Gene

While folic acid is the most common form of vitamin B9 used in supplements and fortified foods, the body must convert it into its active form, methyl folate (5-MTHF), for proper utilisation. This conversion is carried out by the MTHFR (methylenetetrahydrofolate reductase) enzyme. However, genetic variations in the MTHFR gene can reduce the efficiency of this process, potentially leading to lower active folate levels and an increased risk of fertility issues, neural tube defects, and pregnancy complications.

For individuals with MTHFR mutations, supplementing with methyl folate instead of folic acid may support better absorption and utilisation. However, personalised guidance from a healthcare professional is recommended to determine the best approach based on genetic and nutritional needs.

Food Sources of Folic Acid

Folate is naturally present in many foods, and folic acid is also added to fortified products. Good dietary sources include:

Leafy green vegetables: Spinach, kale, Brussels sprouts, cabbage, broccoli
Legumes: Chickpeas, lentils, black-eyed beans, kidney beans
Fortified foods: Breakfast cereals, bread, pasta (check labels for folic acid content)
Nuts and seeds: Almonds, sunflower seeds
Animal products: Eggs, poultry, pork, shellfish, liver
Fruits: Oranges, avocados
Whole grains: Wheat bran, brown rice

Since folate is water-soluble and sensitive to heat, it can be lost during cooking. To preserve folate levels, steaming or microwaving vegetables rather than boiling them is recommended.

The Risks of Folic Acid Deficiency

A lack of folic acid can lead to several health complications beyond fertility concerns, including:

Macrocytic anaemia: Resulting in fatigue, weakness, and difficulty concentrating
Increased risk of birth defects: Particularly neural tube defects
Cognitive impairments: In both children and adults
Depression and mood disorders: Folic acid plays a role in neurotransmitter synthesis

Certain conditions and lifestyle factors, such as Crohn’s disease, coeliac disease, excessive alcohol consumption, and certain medications (e.g., methotrexate, diuretics), can increase the risk of folate deficiency.

Can You Take Too Much Folic Acid?

While folic acid is generally safe, excessive supplementation can mask vitamin B12 deficiency, which can lead to neurological complications if left untreated. For most adults, long-term folic acid intake should not exceed 1 milligram per day unless prescribed by a healthcare provider.

Conclusion

Ensuring adequate intake through a balanced diet and, when necessary, supplementation can enhance fertility, support a healthy pregnancy, and reduce the risk of complications. For those trying to conceive, being mindful of folic acid intake is a simple yet powerful step towards optimising reproductive health and ensuring the best start for future generations.

Sources:

Funmi

Funmi is a registered Associate Nutritionist (ANutr) with the Association for Nutrition (AfN). She is passionate about helping people improve their relationship with food, enjoy movement, and find a sustainable approach to healthy living through her virtual practice, Pattern Nutrition. A foodie herself, Funmi loves supporting others in creating a balanced, tasty lifestyle without the side of diet culture.