Recurrent pregnancy loss (RPL) is generally defined as two or more losses. In fact, it’s sometimes even three or more losses, depending on which guidelines you’re reading. A thorough workup into the underlying cause(s) is very rarely done until three recurrent losses occur1. The lack of earlier investigation can be extremely disempowering when trying to conceive. Furthermore, the trauma of experiencing several losses in a row can be heartbreaking for women and couples.
Currently, the cause of RPL is only identified in approximately 50% of cases2. Despite this, we know that many factors can be investigated and addressed earlier on to reduce the risk of future loss.
Vitamin D status is just one of the factors that need to be assessed in any case of RPL but is commonly overlooked.
Vitamin D Actions and Importance
Vitamin D deficiency is so common in North America that OHIP no longer covers blood testing for it. Instead, we assume everyone is deficient and recommend that everyone supplement. Unfortunately, this approach doesn’t address the range in deficiencies that can be seen. Nor can it direct the correct and safe dosing for an individual’s specific levels.
Vitamin D plays an enormous range of roles, and is now considered to act more like a hormone in the body.
Just some of Vitamin D’s roles include:
- Bone health
- Mood support
- Immune system balance
- Ovulation and fertility support
- Anti-inflammatory action
Vitamin D, Immune System Balance and RPL
Vitamin D plays an important role in modulating and supporting a balanced immune system3. It’s well established that many immune system cells have Vitamin D receptors. Additionally, we know that some Vitamin D production takes place in our reproductive tissues2. Furthermore, there are Vitamin D receptors present in the placenta, suggesting that Vitamin D may play a role in the immune balance between mother and baby6 as well.
Recent research points to immune system dysregulation as a likely—and often overlooked—cause in many RPL cases2. An activated immune system can affect healthy implantation and increase the likelihood of a loss2. A systematic review of the research on this topic to date found that there was a high prevalence of Vitamin D deficiency in women experiencing RPL3.
Early on in pregnancy, an immune system shift is required to allow tolerance for the growing baby. This happens because it isn’t identical to the mother’s DNA, and thus can be considered foreign. Vitamin D has been shown to support this healthy shift in the immune system4. One study found that women with sufficient Vitamin D levels in the pre-conception period were more likely to carry to term than those with Vitamin D deficiency7.
Another study found that 47% of patients with RPL were Vitamin D deficient5. Other research shows that women who have experienced RPL and have Vitamin D deficiency also have an increased presence of autoimmune markers. These include anti-thyroid antibodies, ANA, anti-phospholipid antibodies6.
Vitamin D deficiency in pregnancy has been associated with RPL but also with preeclampsia, gestational diabetes, fetal growth restriction, and pre-term labour3.
If you have experienced RPL and haven’t had a thorough workup including your Vitamin D levels, advocate for more testing! Vitamin D should be run along with other markers of immune system function, hormonal balance and inflammation.
References
- Definitions of infertility and recurrent pregnancy loss. (2008). Fertility And Sterility, 90(5), S60. doi: 10.1016/j.fertnstert.2008.08.065
- Schröder-Heurich, B., Springer, C., & von Versen-Höynck, F. (2020). Vitamin D Effects on the Immune System from Periconception through Pregnancy. Nutrients, 12(5), 1432. doi: 10.3390/nu12051432
- Gonçalves, D., Braga, A., Braga, J., & Marinho, A. (2018). Recurrent pregnancy loss and vitamin D: A review of the literature. American Journal Of Reproductive Immunology, 80(5), e13022. doi: 10.1111/aji.13022
- Sharif, K., Sharif, Y., Watad, A., Yavne, Y., Lichtbroun, B., & Bragazzi, N. et al. (2018). Vitamin D, autoimmunity and recurrent pregnancy loss: More than an association. American Journal Of Reproductive Immunology, 80(3), e12991. doi: 10.1111/aji.12991
- Ota, K., Dambaeva, S., Han, A., Beaman, K., Gilman-Sachs, A., & Kwak-Kim, J. (2013). Vitamin D deficiency may be a risk factor for recurrent pregnancy losses by increasing cellular immunity and autoimmunity. Human Reproduction, 29(2), 208-219. doi: 10.1093/humrep/det424
- Zhao, H., Wei, X., & Yang, X. (2021). A novel update on vitamin D in recurrent pregnancy loss (Review). Molecular Medicine Reports, 23(5). doi: 10.3892/mmr.2021.12021
- Mumford, S., Garbose, R., Kim, K., Kissell, K., Kuhr, D., & Omosigho, U. et al. (2018). Association of preconception serum 25-hydroxyvitamin D concentrations with livebirth and pregnancy loss: a prospective cohort study. The Lancet Diabetes & Endocrinology, 6(9), 725-732. doi: 10.1016/s2213-8587(18)30153-0
