Vitamin D in pregnancy: functions, benefits and foods 2026

Throughout the entire pregnancy, and even before conception occurs, there are a series of essential nutrients for both the mother and the fetus. In this way, if some type of deficiency occurs, complications may arise, the severity of which will depend on which vitamin or mineral the deficiency presents. A good example is vitamin D, less known if possible during pregnancy (compared to other more popular nutrients), but just as important.

What is vitamin D?

Lavitamin It is a fat-soluble vitamin, which means that it can be dispersed and stored in fat (this is what happens with other equally fat-soluble vitamins, such as vitamin A, E and K, as well as some phytonutrients, such as carotenoids). It is necessary to enjoy a healthier body, in addition to maintaining strong bones.

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Commonly known as the “sunshine vitamin,” this vitamin is formed when our skin is exposed to the sun's ultraviolet rays. Of course, it is also possible to find it in certain foods and in some dietary supplements.

What are the functions of vitamin D? And in pregnancy, why is it so important?

The main function of vitamin D is to help the body absorb calcium and phosphorus in the small intestine. It helps prevent bone loss, as well as the softening of bones.

For this reason, people with a vitamin D deficiency can develop soft, weak and brittle bones, a condition known as rickets in children, and osteomalacia in adults.

During pregnancy, vitamin D is essential for the normal and healthy development of the baby's bones. Its deficiency is related to preeclampsia, which is a serious complication of pregnancy, characterized by high blood pressure and signs of damage to some organs, such as the liver and kidneys.

A study published in 2010 showed that taking 4,000 IU per day of vitamin D helped reduce premature births during pregnancy, in addition to preventing other problems, such as preeclampsia or gestational diabetes.

But this recommendation should be taken with a grain of salt, since at the time it caused some controversy, given that many specialists believe that very high doses of vitamin D during pregnancy could cause birth defects. However, there is no evidence that supplementation with this vitamin, even in amounts greater than 10,000 IU, is toxic.

During breastfeeding it is just as important

We always tend to talk about the benefits of most nutrients throughout pregnancy (or even before conception occurs, as with folic acid), but what about breastfeeding?

The truth is that vitamin D is equally important during breastfeeding, and not only during pregnancy.

For example, it has been shown that babies who are exclusively breastfed, but whose mothers have low levels of vitamin D, are often much more likely to suffer from some problems.

Main sources of vitamin D

We need sunlight so that our body can be able to manufacture vitamin D, so in reality there are several factors that influence the body's ability to produce and absorb it, such as where we live, the season in which we are, how much time we spend outdoors... Even if we have - or not - healthy intestines, which will ensure correct absorption.

However, it is enough to spend more time in the sun to get a good amount of vitamin D. Of course, always with proper protection.

The reality is that few foods contain vitamin D naturally. Hence some foods have been enriched with it (or fortified). This means that vitamin D has been added to its composition. However, we find this vitamin in the following foods:

• Salmon
• Sardines
• egg yolk
• Shrimp

Additionally, you can find vitamin D in some of the following foods and drinks; yes, always enriched or fortified:

• Milk
• Cereals
• Yogurt
• orange juice

Are vitamin D supplements necessary during pregnancy?

It is not entirely clear whether vitamin D supplements, either alone or in combination with calcium, have beneficial or harmful effects during pregnancy (for the mother or her baby).

A review was recently published that consisted of updating a review carried out in 2012, and which was later modified and updated in 2016, in which the effect of vitamin D supplementation during pregnancy was evaluated.

It was found that giving pregnant women supplements of this vitamin "probably" reduces the risk of preeclampsia, gestational diabetes and low birth weight. In addition, it would reduce the risk of suffering serious bleeding after childbirth.

However, other much larger and higher quality randomized trials would be necessary to evaluate these effects, in relation to the risk of adverse effects in pregnant women.

Supplementation with vitamin D could be necessary in those cases in which there is a deficiency of this vitamin, given that low blood concentrations of it in pregnant women have been associated with pregnancy complications.