Despite Singapore’s sunny weather, most pregnant women have inadequate vitamin D, increasing the risk of birth complications.

While mothers-to-be are generally mindful of their nutritional intake, one commonly neglected nutrient is vitamin D. In Singapore and around the world, there is a high prevalence of vitamin D deficiency in pregnant women, and this is increasing their risk of birth complications.

A study by KK Women’s and Children’s Hospital (KKH) in 2021 found that during the COVID-19 pandemic, up to 90 per cent of pregnant women had insufficient vitamin D. “Getting an adequate amount of vitamin D is proven to reduce the risk of complications in pregnancies, such as preterm birth and low birth weight in infants,” said Professor Jerry Chan, Senior Consultant, Department of Reproductive Medicine, KKH, and Director, SingHealth Duke-NUS Maternal and Child Health Research Institute (MCHRI).

Vitamin D is available in two main forms — vitamin D2 and D3. While these can be obtained from food sources, vitamin D3, commonly known as the ‘sunshine vitamin’, is also produced in the skin upon sun exposure.

Given that Singapore is sunny all year round, it may seem odd that so many people lack vitamin D. Prof Chan pointed out that this may be because sun protection awareness in Singapore is very high. People frequently wear hats and cover up with clothing for extra sun protection, spend more time indoors, or lead sedentary lifestyles.

This is especially true for expectant mothers, who tend to stay indoors and use sun protection when outdoors. The pandemic has also kept more people indoors, he added.

Since vitamin D deficiency is common, Prof Chan recommends that pregnant women take a daily vitamin D supplement at doses of 800 to 1,000 IU as soon as they know they are expectant. Even women planning for a baby will benefit from vitamin D supplements. Proven to be safe, this dosage will ensure an adequate supply of vitamin D to the foetus. Vitamin D toxicity is a very rare condition, and can occur when taken at 10 to 25 times the recommended upper limit for the supplements in repeated doses.

In October 2021, the MCHRI launched a series of Healthy Early Life Moments in Singapore (HELMS) initiatives. One of the key interventions for women during preconception involves supplementing nutrition with vitamin D to improve overall health and reduce the risk of complications.

“Vitamin D plays a key role in supporting the immune system and muscle function, and together with calcium, helps keep bones strong and healthy. The Endocrine Society states that at least 1,500 to 2,000 IU of vitamin D per day from all sources, including supplements, diet and sunshine, may be needed to maintain a healthy level of vitamin D in the body to maximise its effect on calcium, bone and muscle metabolism,” Prof Chan said.

He also recommended spending 10 to 15 minutes in the sun daily to obtain adequate vitamin D, while preventing sunburn by avoiding excessive sun exposure and using sun protection such as sunscreen. Pregnant women should also eat foods rich in vitamin D, including oily fish like salmon and mackerel, egg yolk, or foods fortified with vitamin D, such as breakfast cereals and dairy products.

An all-rounded approach to holistic health and nutrition will reduce the risk of birth complications, and ensure that both mother and baby are healthy during pregnancy and beyond.

Read more: The complete pregnancy guide by KKH, week by week, click here. 

According to the Health Sciences Authority, the maximum daily limit for vitamin D is 1,000 IU. Vitamin D is a nutrient that helps the body absorb and regulate calcium in the blood. Vitamin D toxicity is rare; however, when a person consumes too much, it can lead to dangerously high levels of blood calcium, a condition called hypercalcemia. Symptoms of vitamin D toxicity are directly related to excess calcium in the blood, which can cause nausea, vomiting, loss of appetite, frequent urination, weakness, and bone pain.

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