How Vitamin D May Impact Your Fertility

Written By: Dr. Salli Tazuke, a board-certified reproductive endocrinologist and infertility specialist at CCRM Fertility of San Francisco

While vitamin D is known for playing an integral role in bone development by helping your body to absorb calcium, did you know it can also impact your immune system, heart health, digestion and even your fertility? 

Here is how vitamin D may affect fertility and how you can make sure you’re getting the right amounts for your health.

VITAMIN D AND FEMALE FERTILITY AND PREGNANCY

Lower vitamin D levels were associated with more women not conceiving easily on their own, according to a 2017 study.  

The stakes can be higher if you need fertility treatments, such as in vitro fertilization (IVF), to conceive. Research shows women undergoing assisted reproductive technologies (ART) who have adequate levels of vitamin D had more positive pregnancy tests, an easier time getting pregnant, and higher rates of live births compared to those with lower vitamin levels. 

If you’re already pregnant, you can develop complications if your vitamin D levels aren’t within normal parameters. Research from a 2017 study reported that women with low levels of vitamin D had more high blood pressure in pregnancy, pre-eclampsia, and gestational diabetes than women with normal vitamin D levels. Another study found not having adequate levels of vitamin D in pregnancy had more preterm birth and a baby who is small for gestational age (babies who are below the 10th percentile for their weight when their born) compared to women with adequate levels of vitamin D. 

VITAMIN D AND MALE FERTILITY

Vitamin D is important for male overall health, but it also can help increase testosterone levels. While low testosterone doesn’t necessarily mean your fertility is affected, it does impact your libido and ability to have an erection, and it helps with sperm production. Research indicates increasing your vitamin D levels can boost your testosterone.

Lower vitamin D levels in men were associated with poorer semen quality, especially when it comes to sperm motility, according to one 2017 study. Sperm motility is how well sperm can move and travel through the female reproductive tract.   

NORMAL VITAMIN D LEVELS

Normal 25-hydroxy vitamin D levels range from 25-100ng/ml. About 40% of people in the United States are deficient in vitamin D. It’s important to make sure your levels are in normal range, especially if you are trying to conceive. In a 2019 Reproductive Health study of 500 participants undergoing ART, only 16% of people had normal levels of vitamin D.

VITAMIN D DOSAGE

The National Osteoporosis Foundation recommends that all adults consume 800-1000 IU of Vitamin D3 per day.  If you have deficient levels of vitamin D, you can take higher dosages of vitamin D3

Here are several ways you can boost your vitamin D level. 

• Get some sunshine: The sun is one of the best sources of vitamin D. Aim to get about ten minutes of sunlight on your skin daily and longer if you have darker skin. Don’t forget to apply sunscreen if you plan to be outside longer than that.
• Eat seafood and fatty fish: These are some of the foods highest in vitamin D. Some examples are salmon, tuna, oysters, and mackerel. Wild-caught fish contain higher vitamin D levels than farmed fish. 
• Eat foods containing vitamin D: These are foods have naturally high levels of vitamin D or have been fortified with vitamin D: dairy and plant milks, orange juice, cereals, yogurts, and tofu. (Make sure to check the labels for vitamin D level)
• Supplements: Sometimes sunshine and diet aren’t enough, and you may need to supplement vitamin D. The amount you should take depends on what your vitamin D levels are. 
  • If your level is >30ng/ml:  You should take 400-800 IU daily.
  • If your level is between 20-30ng/ml (deficiency):  It is recommended that you take 1000 IU daily (available over the counter) and recheck level in 12 weeks.
  • If your level is less than or equal to 20ng/ml (deficiency):  It is recommended that you take 50,000 IU of Vitamin D once a week for 8 weeks (to be prescribed by a physician), then take 2,000 IU daily (available over the counter) and recheck level in 12 weeks.
  • If your level is <10ng/ml:  In addition to taking 50,000 IU once a week, you will also need to be seen by an endocrinologist for long-term follow up care.

Vitamin D is essential for fertility health, but many people don’t have the levels they need. If you’ve been struggling to conceive, learn more about your fertility options at ccrmivf.com.