Published on April 18, 2023
Several studies outline the research on vitamin D, fertility, and pregnancy success among both men and women with or without PCOS
Key Points
- Compared to women whose vitamin D levels were sufficient at the beginning of pregnancy, women who were vitamin D deficient had a 94% significantly increased risk of miscarriage, and women who were either deficient or insufficient had a 60% significantly increased risk of miscarriage
- Pregnant women who were vitamin D deficient were 4 times more likely to have recurrent spontaneous abortion compared to those who were not vitamin D deficient
- Another study showed that 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; there was a 3 times higher chance of pregnancy when the male partner had a vitamin D level of at least 30 ng/ml (75 nmol/L) compared to males with levels below 30 ng/ml
Next week (April 23-29) is National Infertility Awareness Week. According to the World Health Organization, one in every 6 adults worldwide experience infertility. The following information might help someone you know, or someone in your circle, who might be struggling to start a family.
Please share this important information!
How Vitamin D Levels among Men and Women Affect Fertility and IVF Outcomes
Vitamin D is necessary for all stages of the life-cycle, and especially for pregnancy. Numerous studies have found that higher vitamin D levels in the range of 40-60 ng/ml (100-150 nmol/L) during pregnancy reduce the risk of adverse maternal and infant outcomes, including preterm birth, hypertensive disorders of pregnancy (preeclampsia) and gestational diabetes.
Vitamin D is also involved in the process of conception, implantation and the development of the placenta, and vitamin D levels in both men and women can have an effect on fertility and the chances of having a live birth.
In women, vitamin D plays key roles the production of the ovarian steroid hormones progesterone, estradiol, and estrone, as well as follicular stimulation hormone (FSH) and follicular maturation and selection. During fertilization, the vitamin D level of the woman facilitates the sperm selection process and influences the selection of the ‘best sperm.’ For outcomes among IVF patients, vitamin D levels are strongly correlated with the rate of success, independently of age, BMI, ethnicity, and the number of embryo transfers.
Studies in men have shown a correlation between vitamin D sufficiency and improved sperm count, motility, and increased fertility overall, as well as a positive association between vitamin D and testosterone levels among older men.
Vitamin D Deficiency Occurs in 67-85% of PCOS Cases
A paper by Várbíró et al. reviewed findings from research on vitamin D in men and women, fertility, IVF success rates, and pregnancy among women with or without Polycystic Ovary Syndrome (PCOS). PCOS is one of the most frequent causes of infertility among women, with evidence that both insulin resistance and vitamin D status play key roles. Among PCOS patients, vitamin D supplementation has been shown to have positive effects on the menstrual cycle, follicular maturation, and endometrial receptivity during implantation of the embryo.
A study included in the review, by Pal et al., found that vitamin D level was an independent predictor of reproductive success rates in women with PCOS following induction of ovulation, with the probability of ovulation and live birth increasing as vitamin D levels increased.
Live births were 44% lower among women with PCOS whose vitamin D levels were below 30 ng/ml (75 nmol/L) and 4 fold higher among women with vitamin D levels of 45 ng/ml (112.5 nmol/L) or higher. For these women, the ratio of live births increased by 2% for every one ng/ml (2.5 nmol/L) increase in vitamin D levels.
Women with PCOS undergoing IVF also have a higher chance of both implantation and occurrence of clinical pregnancy when vitamin D levels were higher, and vitamin D levels have also correlated with embryo quality.
Miscarriage Risk 94% Higher if Vitamin D Deficient
A 2022 meta-analysis by Tamblyn et al. included data from 10 studies with a total of 7,663 women to assess the predictive value of vitamin D status on miscarriage (loss during the first or second trimester) and recurrent miscarriage. Vitamin D levels taken during the first or early second trimester (latest around 14 weeks) were used for the analysis; one study also measured preconception vitamin D levels. Vitamin D deficiency was defined as less than 20 ng/ml (50 nmol/L), insufficiency as 20-30 ng/ml (50-75 nmol/L), and sufficiency as at least 30 ng/ml (75 nmol/L).
The analysis found that, compared to women whose vitamin D levels were sufficient
- women who were vitamin D deficient at the beginning of pregnancy had a 94% significantly increased risk of miscarriage
- women who were either deficient or insufficient had a 60% significantly increased risk of miscarriage
Among the women whose preconception vitamin D levels were measured, higher preconception vitamin D was associated with a 12% reduced risk of pregnancy loss.
The authors concluded that “Vitamin D deficiency and insufficiency are associated with miscarriage.”
Recurrent Spontaneous Abortion 4 Times More Likely with Low Vitamin D
Recurrent spontaneous abortion, or recurrent miscarriage, is defined as two or more successive pregnancy losses; usually, the loss occurs prior to 20 weeks from the last menstrual period. Another 2022 meta-analysis by Chen et al. looked at data from 14 studies to determine the association between vitamin D level and the occurrence of recurrent spontaneous abortion (RSA). Based on the analysis, pregnant women who were vitamin D deficient were 4 times more likely to have recurrent spontaneous abortion compared to those who were not vitamin D deficient.
Vitamin D Level of Male Partners Affects Pregnancy Success Rate
Another study looking at pregnancy success and vitamin D levels among male partners showed that 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. In fact, there was a 3 times higher chance of pregnancy when the male partner had a vitamin D level of at least 30 ng/ml (75 nmol/L) compared to males with levels below 30 ng/ml. 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.
Other Nutrients Important for a Healthy Pregnancy
Other nutrients, including magnesium, calcium, B-vitamins, and others, are essential for a health pregnancy and baby. Omega-3 fatty acids are especially important, so much that the Australian Government, Department of Health officially made the recommendation for daily supplementation with omega-3 long-chain polyunsaturated fatty acids (800 mg docosahexaenoic acid [DHA] and 100 mg eicosapentaenoic acid [EPA]) for all pregnant moms!
Download & Share the Full Healthy Conception & Pregnancy Infographic Here
Toxic Elements Can Also Increase Miscarriage Risk
During pregnancy, toxic elements such as lead stored in bones can be released and passed from the mother’s body to the baby which may result in miscarriage, premature birth, low birth weight, learning or behavioral problems, or damage to the baby’s brain, kidneys, or nervous system. Cadmium is another toxic element that can also accumulate in the kidneys and thyroid gland, and can contribute to thyroid issues, kidney disease, infertility, uterine fibroids, and other reproductive tract diseases if the build-up is high enough.
Take steps for your own reproductive health by ensuring optimal vitamin D levels and testing for essential and toxic elements – for your family and loved ones as well – by measuring at home today.
How Can You Use this Information for YOUR Health?
Having and maintaining healthy vitamin D and other nutrient levels can help improve your health now and for your future. Measuring is the only way to make sure you are getting enough!
STEP 1 Order your at-home blood spot test kit to measure vitamin D and other nutrients of concern to you, such as omega-3s, magnesium, essential and toxic elements (zinc, copper, selenium, lead, cadmium, mercury); include hsCRP as a marker of inflammation or HbA1c for blood sugar health
STEP 2 Answer the online questionnaire as part of the GrassrootsHealth study
STEP 3 Using our educational materials and tools (such as our dose calculators), assess your results to determine if you are in your desired target range or if actions should be taken to get there
STEP 4 After 3-6 months of implementing your changes, re-test to see if you have achieved your target level(s)
