Published on September 29, 2021

Study shows women with higher vitamin D levels at the beginning stage of labor reported less pain during labor and after birth

Key Points

  • Vitamin D levels of at least 40 ng/ml (100 nmol/L) have been associated with multiple positive outcomes for prenatal and newborn health, including decreased risk of preterm birth, preeclampsia, gestational diabetes, and cesarean section
  • Vitamin D levels of at least 50 ng/ml (125 nmol/L) have also been associated with peak musculoskeletal performance
  • A recent study shows that vitamin D levels at the beginning stage of labor were related to the level of pain reported during and after birth; higher vitamin D levels were related to lower pain scores, with the greatest significance at the beginning and middle stages of labor and in the postpartum period
  • All women who are pregnant or are considering pregnancy should aim for a vitamin D level of at least 40 ng/ml

Vitamin D levels of at least 40 ng/ml (100 nmol/L) have been shown to improve health outcomes for both the mother’s pregnancy and baby’s overall health, and has been linked to a lower risk of preterm birth, pre-eclampsia, gestational diabetes, bacterial vaginosis, cesarean section, postpartum depression, and more. Unfortunately, more than 80% of pregnant women and virtually 100% of pregnant African American women have vitamin D levels below 40 ng/ml.

Vitamin D Levels Linked to Muscle Function & Pain

Vitamin D provides many benefits to musculoskeletal health, including having a role in muscle function, coordination, balance, inflammation, and tissue repair and healing after an injury. Vitamin D deficiency has been associated with neuromuscular diseases, muscle weakness and increased risk of injury, as well as chronic pain.

Proper muscle function is essential during the birthing process, with muscle contractions working to efficiently dilate the cervix and enable the mother to push the baby out of the uterus through the birth canal. Vitamin D is essential to proper muscle function, with cumulative research showing that peak musculoskeletal performance may occur with a vitamin D level of at least 50 ng/ml (125 nmol/L).  This relationship between vitamin D and muscle function could be one reason why a study found that women who had a vitamin D level below 15 ng/ml were almost 4 times more likely to have a primary cesarean section compared to women with higher levels of vitamin D.

Could Vitamin D Levels Affect Pain During Labor?

A study by Koyucu R. and Ozcan T. aimed to see if there was a relationship between vitamin D levels at the start of labor and the level of pain through each stage of labor and after birth. The study enrolled 127 women between the ages of 18 and 40 years old, who were pregnant to term (37-40 weeks), and were at the early active phase of labor with 2-3 cm cervical dilation. Women with complications that may have affected labor pain were excluded from the study. All women had their vitamin D levels measured at the beginning of labor. Labor pain was assessed using the Visual Analog Scale at the initial stage with 2-3 cm cervical dilation (VAS0), then at 4-7 cm (VAS1), and finally at 8-10 cm (VAS2). Postpartum pelvic pain (VASPP) and length of labor were also assessed and measured.

What did the study find?

The average vitamin D level among the women at the beginning of labor was 24 ng/ml (60 nmol/L). Average pain scores were 4.5 at VAS0, 6.5 at VAS1, 8.6 at VAS2, and 2 at VASPP.

Click to Enlarge & Print

As illustrated in the charts above, there was a moderate negative correlation between vitamin D levels and pain during the initial and second phase (VAS0 and VAS1), and between VASPP. The correlation between the vitamin D level and pain at the final phase of labor (VAS2) was also there but was not as significantly correlated. There was no significant correlation between vitamin D levels and the length of labor.

Ensure a Minimum Vitamin D Level of 40 ng/ml for Pregnancy, Birth, and Baby

The benefits of vitamin D go well beyond pregnancy and birth. Vitamin D deficiency in newborns presents an increased risk for impairment in immune function, brain development, and skeletal development, among other things. Health conditions 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. See our Disease Incidence Prevention Chart for Pregnancy and Children for more details and resources.

Testing your vitamin D level regularly and taking steps to keep it at a target level of 40-60 ng/ml (100-150 nmol/L) is important for all stages of health, especially during pregnancy. To know if you are getting enough, make sure you test today!

The Importance of Getting Enough of All Nutrients

Having and maintaining healthy vitamin D levels and other nutrient levels can help improve your health now and for your future. Choose which to measure, such as your vitamin D, omega-3s, and essential minerals including magnesium and zinc, by creating your custom home test kit today. Take steps to improve the status of each of these measurements to benefit your overall health. You can also track your own intakes, symptoms and results to see what works best for YOU.

Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, 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.

Help everyone Move Research into Practice with vitamin D and other nutrients! As a special birthday gift to everyone, in honor of the science, we have created a special scholarship fund for anyone to donate to that will go towards helping others participate. Your donation will allow anyone to get help with funding their participation when they need it.

Text-to-give: Text Daction to 44321 to add to our Scholarship Fund.

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!