Vitamin K for fertility

On this page

1. What is vitamin K?
2. Function and how it works
3. Fertility benefits
4. Recommended daily dose
5. Food sources
6. Cautions and contraindications
7. My Fertility Guide
8. Related pages

1. What is vitamin K?

Vitamin K is a fat-soluble vitamin that exists in three forms: K1 (phylloquinone, from green plants), K2 (menaquinone, from fermented foods and animal products) and K3 (synthetic). Around 90% of our daily intake comes from vitamin K1. Vitamin K is essential for normal blood clotting, bone health and the regulation of calcium in the body.

Reference ranges and recommended intakes vary from country to country — always interpret guidance against the recommendations of your own healthcare authority.

2. Function and how it works

Vitamin K supports fertility through several mechanisms:

1. Blood clotting. Vitamin K is required for the synthesis of clotting factors II, VII, IX and X. Deficiency causes heavy menstrual bleeding (which depletes iron and contributes to anaemia) and easy bruising.
2. Calcium regulation. Vitamin K2 directs calcium into bones and away from soft tissues, working in partnership with vitamin D.
3. Bone health. Vitamin K activates osteocalcin, the protein that builds bone matrix.
4. Cardiovascular health. Vitamin K2 helps prevent calcification of arteries.

3. Fertility benefits

For women experiencing heavy periods (menorrhagia) and the resulting iron deficiency and anaemia, ensuring adequate vitamin K can help reduce blood loss. Together with iron, this addresses one of the most common contributors to fatigue and reduced fertility in women trying to conceive.

4. Recommended daily dose

I recommend a daily dose of 100 mcg of vitamin K, typically obtained as part of a good-quality prenatal supplement or directly from food. For specific bone or cardiovascular indications, vitamin K2 (MK-7 form) is sometimes used at 100–200 mcg per day under professional supervision.

5. Food sources

Vitamin K1 is found in:

1. Cauliflower and broccoli
2. Dark green leafy vegetables (kale, spinach, Swiss chard)
3. Brussels sprouts and cabbage
4. Egg yolks
5. Safflower, rapeseed and olive oils
6. Tomatoes and potatoes
7. Red meat
8. Yoghurt
9. Kelp and seaweed

Vitamin K2 is found in fermented foods such as natto and aged cheeses.

6. Cautions and contraindications

1. Vitamin K supplementation is contraindicated in patients taking warfarin and other vitamin-K-antagonist anticoagulants — discuss with your doctor before supplementing.
2. Most people get adequate vitamin K from food alone if they eat a varied diet including green leafy vegetables.
3. Always consult with a fertility specialist or your doctor before starting any new supplement regime.

7. My Fertility Guide

8. Related pages

• Fertility supplements directory
• Vitamin D — works with vitamin K for calcium regulation
• Calcium
• Iron