Author | Chuan Zhi Xiao Hong Lou: Zhang Yue
Source｜Medical World Obstetrics and Gynecology Channel
In recent years, the public has become increasingly aware of the dangers of vitamin D deficiency, and proper vitamin D supplementation plays an indispensable role in human growth and development, endocrine function, and immunity.
Because a pregnant woman's vitamin D levels directly affect the fetus's vitamin D levels, many mothers start supplementing with vitamin D for their baby's health. But is vitamin D supplementation during pregnancy really that important? What are the consequences of not supplementing? Let's find out today.
What exactly is Vitamin D?
Vitamin D is currently considered a steroid hormone that can promote the absorption of calcium in the intestines, strengthen bones, and increase muscle control and neuromuscular coordination. In the past, it was used as a calcium promoter, and vitamin D was supplemented at the same time as calcium supplementation.
In recent years, more and more literature has shown that vitamin D plays an important role in reproductive endocrinology and can affect human reproduction through multiple pathways. Vitamin D receptors are widely distributed in the reproductive system, including the ovaries, uterus and endometrium. [1]
Multiple animal studies have shown that feeding female rodents a vitamin D-deficient diet and removing vitamin D receptors significantly reduces their fertility. [1] Would the same result occur in humans?
What is the effect of vitamin D on female fertility?
Unfortunately, although vitamin D plays an important role in animal studies, researchers have not shown a strong correlation when assessing the relationship between vitamin D and fertility in healthy individuals. Similarly, two studies conducted in Denmark (153 women) and Italy (146 women) also showed no significant correlation between vitamin D concentration and the probability of conception. [2-3]
Seeing this, you might say that vitamin D doesn't actually play a role in fertility. But that's not entirely true, as some studies have shown that vitamin D deficiency can lead to an increased risk of miscarriage[4]. To be precise, whether vitamin D affects human fertility remains unknown. To date, there is still no sufficiently rigorous scientific experiment to prove the relationship between the two.
How should pregnant women supplement vitamin D?
Having said all that, do pregnant women actually need to supplement with vitamin D? In my opinion, although there is still no definitive conclusion on the relationship between vitamin D and human fertility, it is very important for pregnant women.
Since 25-30 g of calcium is transferred from the mother to the fetus during the entire pregnancy to meet the needs of fetal bone development, it is easy for pregnant women to lose too much bone calcium, and even cause osteomalacia in the mother. Multiple studies have found that vitamin D deficiency in pregnant women may also increase the chances of developing severe preeclampsia, gestational diabetes, and bacterial vaginosis. [5]
In addition, vitamin D can promote fetal bone development and is an essential substance during fetal growth. If the mother is deficient in vitamin D, the fetus will also not get enough vitamin D, which will be detrimental to fetal growth and development, leading to substandard physical signs and even rickets and varying degrees of skeletal deformities. Furthermore, ensuring sufficient vitamin levels in pregnant women may also reduce the incidence of diseases such as cancer, diabetes, and osteoporosis in the fetus later in life. [6]
Therefore, calcium and vitamin D supplementation during pregnancy is essential for both the mother and the fetus. According to the "Chinese Dietary Reference Intakes 2007," we recommend a dietary intake of 5 ug/day of vitamin D for pregnant women in the first trimester, and 10 ug/day in the second and third trimesters. Of course, getting plenty of sunshine and consuming appropriate amounts of wild fish (salmon, herring), animal liver, and eggs are also good ways for expectant mothers to supplement their vitamin D intake!
The health of a pregnant woman and her fetus requires the joint efforts of the pregnant woman, her family, and doctors. In addition to regular prenatal checkups and advice from doctors, pregnant women also need to pay attention to a balanced and reasonable diet, moderate exercise, and a regular sleep schedule to nurture a healthy baby. Stay tuned for the third installment of "How to Eat During Pregnancy"!
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