Low Vitamin D and Fertility

Low Vitamin D and Fertility

Vitamin D, also known as the sunshine vitamin, has gotten major attention over the last 5-10 years. While we know that vitamin D is good for our immune system and mental health, can vitamin D and fertility be connected? Let’s take a look at the stats. 


Vitamin D has indirect effects on egg health. While vitamin D is primarily known for its role in maintaining bone health and supporting the immune system, emerging research suggests it impacts reproductive health.

Vitamin d and fertility

Vitamin D and Female Hormone Balance

Adequate Vitamin D is essential for female reproductive health by its role in promoting hormone synthesis and regulating proteins involved in fertility and pregnancy.


Vitamin D plays a key role in stimulating the enzyme that converts male hormones into estrogen and progesterone (female hormones). Vitamin D also contributes to the synthesis of these hormones which makes it crucial for fertility and pregnancy.


Vitamin D may also have a significant role in fertility by acting on the ovaries. At the ovary level, vitamin D has been shown to enhance ovulation by altering AMH signaling, increasing FSH sensitivity and increasing progesterone production. 


Various studies show that infertile women with higher vitamin D content in plasma and/or follicular fluid levels are more likely to become pregnant after assisted reproductive procedures.

Vitamin D and Female Infertility

There are numerous recent studies that indicate Vitamin D status is correlated with positive fertility outcomes. 


The data from a study of infertile women in Iran proved that severe long-lasting vitamin D deficiency caused by inadequate sun exposure to the skin is likely a cause of reduced ovarian reserve.

Vitamin D status may be of even more significance during fertility treatments such as IVF to conceive. Research shows follicular fluid levels were positively correlated to serum vitamin D levels, fertilization rates were significantly different with the group of women with the highest serum vitamin D having the highest normal fertilization rate and women with the highest serum levels of vitamin D having the highest chance of pregnancy.

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Vitamin D and Egg Quality

While the direct impact of vitamin D on egg quality is not yet fully understood, it is known that vitamin D is involved in various cellular processes and due to its antioxidant effects, may play a role in preventing oxidative stress and DNA damage. Optimal levels of vitamin D could potentially help support healthy egg development and maturation. 

Based on a study of 80 infertile female candidates for IVF and ICSI. A statistically positive correlation was found between vitamin D levels with patient age and implantation rate.  The obtained results suggest that vitamin D without affecting the number and quality of oocytes can independently improve implantation rate and IVF outcome.

Vitamin d and fertility

Vitamin D and Male Fertility

Vitamin D is crucial for overall health, including boosting testosterone levels in men. Low testosterone levels can affect your libido, ability to achieve an erection, and sperm production. However, it does not necessarily affect fertility. Research indicates increasing your vitamin D levels can boost your testosterone.


Low vitamin D levels in men are associated with poorer semen quality, especially when it comes to sperm motility, according to one 2017 study. Sperm motility is important because it has the sperm move and makes its way to meet the egg. If sperm motility is compromised, the egg will not be fertilized.   

Vitamin D levels:

Vitamin D deficiency has been noted to affect approximately 42% of the U.S population. Currently it is one of the most common vitamin deficiencies in the world and is often referred to as the ‘invisible epidemic’. Deficiency can be due to many factors such as climate and lifestyle. It is important to have adequate vitamin D levels especially if you are trying to conceive. 

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Sources of Vitamin D

The Institute of Medicine recommends an intake of at least 600 IU of Vitamin D3 per day with an upper limit of 1,000 IU. 


  1. Sunlight – at least 15 minutes of direct sunlight a day is adequate. *Most efficient form of vitamin D.
  2. Fish-  salmon, tuna, oysters, and mackerel. Wild-caught fish contain higher vitamin D levels than farmed fish.
  3. Foods-  fortified dairy and plant milk, orange juice, cereals, yogurts, and tofu. (Make sure to check the labels for vitamin D levels).


Vitamin D supplementation doses:

Sometimes sunshine and diet aren’t enough, and you may need to supplement vitamin D. The amount you should take depends on what your vitamin D levels are. 

  • If your level is >30ng/ml:  You should take 400-800 IU daily.
  • If your level is between 20-30ng/ml (deficiency):  It is recommended that you take 1000 IU daily (available over the counter) and recheck the level in 12 weeks.
  • If your level is less than or equal to 20ng/ml (deficiency):  It is recommended that you take 50,000 IU of Vitamin D once a week for 8 weeks (to be prescribed by a physician), then take 2,000 IU daily (available over the counter) and recheck level in 12 weeks.

If your level is <10ng/ml:  In addition to taking 50,000 IU once a week, you will also need to be seen by an endocrinologist for long-term follow-up care.

Vitamin d and fertility

It can be concluded that vitamin D plays a significant role in the rate of implantation, fertilization and pregnancy. Though more research is needed to fully establish a definitive link, it is unlikely that a standard dose of Vitamin D and a little extra bit of sunlight will do any harm. If you need advice on what dose or type of vitamin D is best for you, reach out to us to schedule a 30-minute supplement consultation with a Radically Rooted Dietitian.

If you are concerned about your diet and how it can affect your pregnancy, book a consultation with one of our expert-certified dietitians & nutritionists for individualized nutrition & supplementation advice

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