Selenium Deficiency During Pregnancy

Selenium is an essential trace mineral that plays a critical role in thyroid hormone metabolism, antioxidant defence, and immune function. It is incorporated into selenoproteins, which include the glutathione peroxidase family of enzymes that protect cells from oxidative damage. During pregnancy, selenium supports the mother's immune system, helps regulate thyroid function, and contributes to the healthy development of the baby.

The recommended daily intake of selenium during pregnancy is approximately 60 micrograms. Selenium deficiency occurs when dietary intake consistently falls below the amount needed to support these essential functions. The selenium content of foods varies significantly depending on the selenium levels in the soil where crops are grown, making deficiency more common in certain geographic regions.

In India, soil selenium levels vary widely across different states and regions. While coastal areas like Visakhapatnam may have moderate soil selenium, women whose diets rely heavily on foods grown in selenium-poor soils may be at risk. Understanding this nutrient and ensuring adequate intake through a varied diet is an important aspect of prenatal nutrition.

The primary cause of selenium deficiency is consumption of foods grown in selenium-depleted soils. Agricultural practices, soil type, and regional geology all influence the selenium content of grains, vegetables, and other crops. Women whose diets are limited in variety and rely predominantly on locally grown staple grains may be particularly susceptible if those grains come from low-selenium soils.

Dietary factors also play a role. Selenium is found in higher concentrations in protein-rich foods such as fish, meat, eggs, and nuts. Women with low protein intake or those following highly restrictive diets may not consume enough selenium-containing foods. Processing and refining of grains can also reduce their selenium content, as the mineral is concentrated in the outer layers of the grain.

Gastrointestinal conditions that impair nutrient absorption, including Crohn's disease and conditions requiring parenteral nutrition, can contribute to selenium deficiency. Severe morning sickness or hyperemesis gravidarum may limit overall nutrient intake, including selenium. Women on dialysis or those with kidney disease may have altered selenium metabolism and require monitoring.

Mild selenium deficiency may not cause obvious symptoms and is often detected only through blood testing. As the deficiency becomes more significant, symptoms may include fatigue, muscle weakness, and recurrent infections due to impaired immune function. Brain fog, difficulty concentrating, and mood changes may also occur, though these symptoms overlap with common pregnancy experiences.

Because selenium is intimately linked to thyroid function, deficiency can manifest as symptoms of hypothyroidism, including weight gain, cold intolerance, dry skin, and constipation. Hair loss, weak or discoloured nails, and a general decline in overall well-being may indicate low selenium status. In severe and prolonged cases, selenium deficiency can contribute to a form of heart disease called Keshan disease, though this is extremely rare in settings with dietary diversity.

For the mother, selenium deficiency reduces the body's antioxidant capacity, leaving cells more vulnerable to oxidative stress. This has been associated with an increased risk of preeclampsia, a condition characterised by high blood pressure and organ damage. Selenium is also essential for the conversion of the thyroid hormone T4 to its active form T3, so deficiency can exacerbate thyroid dysfunction during pregnancy.

Low selenium levels have been linked to an increased risk of miscarriage, preterm birth, and gestational diabetes in some studies. The mineral also plays a role in preventing excessive inflammation, which is important for maintaining a healthy pregnancy environment. For the developing baby, selenium contributes to the antioxidant defence of the placenta and supports normal growth and immune system development.

Some research suggests that adequate maternal selenium may help reduce the risk of postpartum thyroiditis, an autoimmune inflammation of the thyroid that can occur after delivery. While more research is needed, maintaining adequate selenium status during pregnancy appears to offer protective benefits for both immediate and postpartum maternal health.

Brazil nuts are the single richest food source of selenium, with just one to two nuts providing the entire daily requirement. However, they should be consumed in moderation, as excessive selenium intake can be toxic. Other excellent sources include fish and seafood, particularly tuna, sardines, and prawns, which are readily available in Visakhapatnam's fish markets.

Eggs, chicken, lean meat, and mushrooms are good sources of selenium. Among plant-based foods, sunflower seeds, whole wheat, brown rice, and garlic contain meaningful amounts. The selenium content of grains depends heavily on soil conditions, so consuming a varied diet that includes foods from different regions can help ensure more consistent selenium intake.

Most prenatal multivitamins include selenium in safe amounts, typically around 30-60 micrograms. Standalone selenium supplements are rarely necessary during pregnancy unless a specific deficiency is confirmed through blood testing. If your healthcare provider recommends supplementation, follow the prescribed dosage carefully, as the margin between adequate and excessive selenium intake is relatively narrow.

Discuss selenium status with your obstetrician if you have thyroid disease, a history of recurrent pregnancy loss, or if you are at risk for preeclampsia. Your doctor can order a serum selenium test if clinical suspicion warrants it. Women with autoimmune thyroid conditions should have both thyroid function and selenium levels monitored, as adequate selenium may support better thyroid outcomes during pregnancy.

If you experience symptoms of hypothyroidism, recurrent infections, or unexplained fatigue during pregnancy, mention these to your healthcare provider. Your doctor in Visakhapatnam can evaluate whether selenium deficiency or thyroid dysfunction may be contributing to your symptoms and recommend appropriate dietary adjustments or supplementation. Avoid self-prescribing selenium supplements, as excessive intake can cause selenosis, a toxic condition with symptoms including hair loss, nail brittleness, nausea, and neurological problems.