Vitamin D and the Menstrual Cycle

The menstrual cycle consists of a monthly shedding of the uterus lining also known as “menstruation”, “the menstrual period” or just “the period”. During this time, menstrual blood leaves the uterus via the cervix and through the vagina.

The menstrual period usually lasts between 2 and 7 days, although a period longer than 7 days is considered irregular. Periods can be light or heavy, with heavy periods being described as needing to change a sanitary pad or tampon every 1 to 2 hours. A menstrual period is considered late if it is 7 days past the expected due date, and is considered a missed period after 6 weeks (cycle day 42).

Vitamin D is a fat-soluble steroid hormone, which helps the body to absorb calcium and phosphorus. Although an important nutrient, it is estimated that approximately 1 billion people worldwide have a vitamin D deficiency (<20 ng/mL), and 50% of the population having a vitamin D insufficiency (20–30 ng/mL).¹

Common signs of vitamin D insufficiency can include:

• Fatigue
• Bone pain
• Muscle weakness and/or aches
• Mood changes

Obesity is also associated with lower vitamin D levels, particular in individuals with a body mass index (BMI) greater than 30.² This is because fat cells retain vitamin D, so it is not released into the system.

Over the last 50 years researchers have identified vitamin D receptors in female reproductive tissues including the ovaries, endometrium, fallopian tubes and placenta, suggesting that it plays a key role in women’s reproductive health.^3,4

Vitamin D and the Menstrual Cycle

Research suggests that vitamin D levels can influence the length and regularity of the menstrual cycle.

Vitamin D plays a role in ovarian function (and the menstrual cycle) via its action on anti-mullerian hormone (AMH), which is central to maintaining regular menstrual cycles.⁵

It has been reported that women with regular menstrual cycles have significantly higher vitamin D levels than those with irregular cycles. In fact, women with low vitamin D levels were 13 times more likely to have an irregular menstrual cycle.⁶

Although not thoroughly understood, it is thought that vitamin D deficiency prolongs the follicular stage (when the ovarian follicles mature) of the menstrual cycle and delays ovulation.⁷

Vitamin D and Menstruation

Studies show vitamin D also affects your period (menstruation). Vitamin D deficiency delays ovulation which delays your period.⁸

Vitamin D levels are also linked to menstrual cramps. Low levels of vitamin D can increase menstrual cramps by increasing prostaglandin production and/or reducing intestinal calcium absorption.⁹ In these women, high doses of supplementary vitamin D reduces menstrual pain.^10,11,12

Although vitamin D has been associated with many aspects of the menstrual period including length, regularity and pain, there is currently no evidence connecting vitamin D levels and the heaviness of menstruation in otherwise healthy women with no underlying condition.

However, women with uterine fibroids and low vitamin D levels may experience heavier periods and spotting between periods according to other research. Subsequent vitamin D supplementation in these women reduced menstrual blood loss by almost one third and interrupted the fibroids growth.^13,14

Nevertheless, studies on the impact of vitamin D on menstrual bleeding is currently limited, so future research may increase our understanding.

Vitamin D Supplementation

Vitamin D supplementation can often restore regular menstrual cycles which will cause your period to come earlier for women with previously long cycles, or later for women with previously short cycles.

If your previous periods were light, your subsequent periods may be heavier, after vitamin D supplementation, which usually means your reproductive system is functioning better.

For women with highly irregular cycles since puberty and underlying conditions (e.g. Polycystic Ovarian Syndrome), vitamin D supplementation on its own might only restore very light periods (spotting).

Vitamin D can be taken any time during the menstrual cycle including menstruation. There is currently no evidence taking vitamin D supplements will cause a missed period, especially in cases of vitamin D deficiency.

Nevertheless, it is important to obtain advice about the correct dosage of vitamin D for you from a healthcare professional, as excessively high levels can be toxic and lead to hypercalcemia (too much calcium in the blood) which accelerates the growth of kidney stones.¹⁵ Therefore it is always recommended to have follow-up blood tests during vitamin D supplementation and or lifestyle changes.

A Final Tip from Fertility SCIENCE

Vitamin D plays a significant role in various aspects of the menstrual cycle and fertility.

Research suggests that sufficient levels of vitamin D are linked to more regular menstrual cycles, possibly due to its influence on ovarian function and the follicular phase.

Conversely, vitamin D deficiency is associated with increased menstrual cramps, delayed periods and subfertility.¹⁶

Therefore, vitamin D supplementation will often help restore regular menstrual cycles, although the impact may vary depending on the individual and any underlying health conditions such as obesity or Polycystic Ovarian Syndrome.

As usual it is important to seek advice from a healthcare professional including the appropriate dosage, as excessive vitamin D can have adverse effects.¹⁷ Follow-up blood tests should always be undertaken during vitamin D supplementation, which should also include magnesium levels, as vitamin D is strongly regulated by magnesium.¹⁸

fertilPEDIA

Causes of Irregular Periods

Causes of irregular periods include age, pregnancy, medication, recreational drugs, hormone imbalance, stress, unhealthy bodyweight…. Read more

Treatment of Irregular Periods

Treatment of irregular periods varies according to which WHO Group you fall into and the exact cause. Fortunately, almost all cases of irregular periods…. Read more

References

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2. Drincic A T, et al. (2012). Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity. https://onlinelibrary.wiley.com/doi/10.1038/oby.2011.404 ↩︎
3. Zarnani A H, et al. (2010). Vitamin D3 receptor is expressed in the endometrium of cycling mice throughout the estrous cycle. https://www.fertstert.org/article/S0015-0282(09)03795-9/fulltext ↩︎
4. Shahbazi M, et al. (2011). Expression profiling of vitamin D receptor in placenta, decidua and ovary of pregnant mice. https://www.sciencedirect.com/science/article/abs/pii/S0143400411002347 ↩︎
5. Irani M and Merhi Z, (2014). Role of vitamin D in ovarian physiology and its implication in reproduction: a systematic review. https://pubmed.ncbi.nlm.nih.gov/24933120/ ↩︎
6. Singh V, et al. (2021). Association between serum 25-hydroxy vitamin D level and menstrual cycle length and regularity: A cross-sectional observational study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8717082/ ↩︎
7. Xu J, et al. (2018). Vitamin D3 Regulates Follicular Development and Intrafollicular Vitamin D Biosynthesis and Signaling in the Primate Ovary. https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.01600/full ↩︎
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9. Abdi F, et al. (2021). Role of vitamin D and calcium in the relief of primary dysmenorrhea: a systematic review. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7834752/ ↩︎
10. Moini A, et al. (2016). The effect of vitamin D on primary dysmenorrhea with vitamin D deficiency: a randomized double-blind controlled clinical trial. https://www.tandfonline.com/doi/full/10.3109/09513590.2015.1136617 ↩︎
11. Lasco A, et al. (2012). Improvement of Primary Dysmenorrhea Caused by a Single Oral Dose of Vitamin D: Results of a Randomized, Double-blind, Placebo-Controlled Study https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/1108739 ↩︎
12. Amzajerdi A, et al. (2023). The effect of vitamin D on the severity of dysmenorrhea and menstrual blood loss: a randomized clinical trial. https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-023-02284-5 ↩︎
13. Suneja A, et al. (2021). Effect of Vitamin D3 Supplementation on Symptomatic Uterine Leiomyoma in Women with Hypovitaminosis D. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8189330/ ↩︎
14. Ciavattini A, et al. (2016). Hypovitaminosis D and “small burden” uterine fibroids: Opportunity for a vitamin D supplementation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5207559/ ↩︎
15. Letavernier E and Daudon M, (2018). Vitamin D, Hypercalciuria and Kidney Stones. https://www.mdpi.com/2072-6643/10/3/366 ↩︎
16. Jukic A M, et al. (2019). Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability. https://academic.oup.com/humrep/article/34/11/2163/5606542 ↩︎
17. Marcinowska-Suchowierska E, et al. (2018). Vitamin D Toxicity–A Clinical Perspective. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2018.00550/full ↩︎
18. Uwitonze A M and Razzaque M S, (2018). Role of Magnesium in Vitamin D Activation and Function. https://www.degruyter.com/document/doi/10.7556/jaoa.2018.037/html ↩︎