Published on February 22, 2021

What is Vitamin D Good For? (Part 4: Reproductive Health) – Vitamin D is needed by virtually every cell in the body, and is essential for hundreds of processes each and every day

In this “What is Vitamin D Good For?” series, we have discussed how vitamin D contributes to the health of multiple systems within the body and is necessary for hundreds of physiological processes throughout the day. Vitamin D acts as a protector and regulator so it is able to enhance the functioning of our cells, tissues and organs to keep us healthy. From musculoskeletal and dermatological, to cognitive and mental-emotional wellness, vitamin D has many benefits, and a deficit in vitamin D can lead to impairment or disease in each of these systems – from brittle bones to heart disease and cancer. With this in mind, why take a chance at being deficient in vitamin D?

Today, we take a look at why vitamin D is important to the health and function of the reproductive system, for both men and women.

From Pre-Conception to a Healthy Baby, Your Reproductive System Needs Vitamin D

Vitamin D is necessary for all stages of the life-cycle. Numerous studies have found that higher vitamin D levels during pregnancy reduce the risk of adverse maternal and infant outcomes. It is also likely that vitamin D is involved in the process of conception, implantation and the development of the placenta. In fact, vitamin D deficiency is even linked with infertility.

One example of how vitamin D levels affected conception rates among women can be seen in the chart below, which illustrates the probability of conception taking longer than six menstrual cycles among groups of varying levels of vitamin D.

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Overall, women with a vitamin D level of at least 50 ng/ml (150 nmol/L) had a 71% lower probability of conception taking longer than 6 cycles compared to women whose vitamin D levels were less than 20 ng/ml (50 nmol/L).

Dads Need Vitamin D, as well as Moms!

Findings from studies such as the one illustrated in the next chart support the importance of vitamin D for male partners when it comes to increasing the chances of conception, a healthy pregnancy and baby. The pregnancy rate per patient and per cycle as well as delivery rate per patient and per cycle were all significantly higher among the couples whose male partner had a higher vitamin D level compared to the lower vitamin D.

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There was also a tendency towards a higher rate of miscarriage in the group with lower male vitamin D levels, although this particular finding was not statistically significant.

Vitamin D is Especially Important for a Healthy Pregnancy

Pregnancy affects every organ system and metabolic pathway in the body. Blood volume increases, an entirely new organ is grown (the placenta), the breasts are preparing to produce milk, and a whole new person is growing and relying on mom for nutrition. Adjustments in nutrient metabolism are driven by hormonal changes and baby’s needs. It is not surprising then that alterations in vitamin D metabolism also occur. Vitamin D levels in the range of 40-60 ng/ml (100-150 nmol/L) are especially protective during pregnancy, and have been shown to reduce complications including preterm birth, hypertensive disorders of pregnancy (preeclampsia) and gestational diabetes – and is the reason for GrassrootsHealth’s Protect Our Children NOW! D*action Project. Some of the results from this project have shown that women with vitamin D levels at or above 40 ng/ml (100 nmol/L) had a 62% lower risk of preterm birth compared to women with levels less than 20 ng/ml (50 nmol/L) (p<0.0001). This lower risk remained after adjusting for socioeconomic variables.

The Pregnancy Disease Risk Reduction Chart below shows findings from other studies that have compared prenatal and newborn health outcomes to vitamin D levels. It illustrates the percent lower risk at a given vitamin D level compared to a common reference level of 25 ng/ml (62 nmol/L), which is the approximate average level of the U.S. population.

Click to Enlarge & Download (ng/ml)
Click to Enlarge & Download (nmol/L)

Bottom line: Ensuring a vitamin D level in the range of 40-60 ng/ml (100-150 nmol/L) during pregnancy is an effective way to reduce the risk of many complications for both mom and baby!

Vitamin D Levels in Pregnancy Can Affect the Future Health of the Baby

The benefits of vitamin D go well beyond pregnancy as well. Vitamin D deficiency in newborns presents an increased risk for impairment in immune function, brain development, and skeletal development, among other things. Health conditions in the child that have been associated with prenatal vitamin D deficiency include asthma, ear and lung infections, autism, type 1 diabetes and other autoimmune conditions, and an increased risk for certain cancers and cardiovascular disease later in life.

The “Barker Hypothesis,” also known as the “The Fetal Origins Hypothesis,” theorizes that certain adult-onset diseases originate from nutritional deficiencies during the perinatal period (during pregnancy or in early infancy). These damages are irreversible beyond certain critical points in development, even following full nutrient repletion. In the publication “Is Vitamin D Inadequacy in Early Life an Instance of the ‘Barker Hypothesis’?“, Dr. Robert Heaney evaluates prenatal vitamin D deficiency as part of the Barker hypothesis, and correlates it to diseases with an onset later in life such as Multiple Sclerosis (MS), Type 1 Diabetes, Preeclampsia, Schizophrenia, and other cognitive function and learning disabilities.

Summary of Overall Benefits of Vitamin D for Reproductive Health

Vitamin D functions in the reproductive system to:

  • Regulate hormonal pathways, follicular development, fertility and conception time
  • Important for sperm production
  • Important for normal fetal development
  • Essential to a healthy pregnancy, birth and baby

Reproductive Diseases associated with low vitamin D include:

Other Important Co-Nutrients for Reproductive Health

Don’t forget that vitamin D works along with other essential nutrients for our health. For our reproductive health, these include:

Are You Getting Enough Vitamin D to Create Healthy Babies?

With almost 90% of the general population having vitamin D levels below the recommended 40-60 ng/ml (100-150 nmol/L), it is obvious that most people need more vitamin D. While most of us cannot achieve a vitamin D level of 40-60 ng/ml from sun alone, either due to our lifestyle, where we live, or other circumstances, we can certainly reach those levels with the right amount of supplementation.

Below is a guide for how much you might need, and who may need more. Your levels can be tested safely at home – order your home test kit today.

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By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!

We now have a NEW GIFTING SERVICE that allows you to quickly send ‘Gift Cards’ to friends, family and coworkers who you consider might need immediate access to testing, and to Claim the Joy of Your Health TODAY. Give the gift today!

What does the Research Say about Vitamin D & COVID-19?

It’s TIME to start saving lives! If you can help PREVENT the majority of the death, it’s time! What’s it costing you/us not to take action NOW?

There is much published research that supports a clear link between vitamin D and COVID-19 showing that higher vitamin D levels are related to:

a decreased risk of testing positive for COVID-19

increased viral SARS-CoV-2 RNA clearance

better clinical outcomes among patients with COVID-19

less severe COVID-19 disease

decreased risk of death due to COVID-19

Be sure to educate yourself on the benefits and importance of vitamin D for immune health, and take steps to ensure you and your loved ones are getting enough.

You can review all of the COVID-19 and immune health information we have shared on this page.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!