Vitamin D Deficiency and Pregnancy

What is Vitamin D?

Vitamin D is a fat-soluble vitamin that plays a central role in calcium and phosphorous metabolism, which is critical for bone formation and maintenance.

Why is Vitamin D important?

Deficiency of this vitamin years ago resulted in rickets. New studies have demonstrated a resurfacing of vitamin D deficiency worldwide. This deficiency is especially critical in the pregnant and lactating woman. Studies have shown how important vitamin D is to skeletal, cardiovascular, and neurological development in the infant.Other studies have shown deficiencies linked to diabetes, asthma, and schizophrenia in children. Infants born to mothers with vitamin D deficiency had poor growth, and defects in enamel formation of teeth. A newborn’s vitamin D level is completely dependent on maternal levels.

Vitamin D is believed to be critical in placental development and function, which may be associated with other complications during pregnancy including miscarriage, preeclampsia, and preterm birth. Low vitamin D levels have been linked to bacterial infections in the vagina in the first trimester of pregnancy. This can increase the risk of preterm birth and adverse pregnancy outcomes. There is one study that associates a four times greater risk of cesarean section with women that have low Vitamin D levels believed to be due to the fact that skeletal muscle contains vitamin D receptors and deficiency can result in muscle weakness and poor strength in labor. Vitamin D also regulates calcium levels and with deficiency, muscle strength is lowered in labor.

Where do we get Vitamin D?
Vitamin D is obtained from sunlight, diet, and supplements.

Sun—Vitamin D is absorbed from the sun in an inactive form and then converted by the liver and the kidney to its active form.

Diet—Very few food sources contain vitamin D. Oily fish such as salmon, sardines, mackerel, and tuna along with egg yolks, and fish liver oils.

Supplements—Foods can be fortified with vitamin D such as milk, orange juice, some cereals, yogurt, cheese, and butter. Over the counter supplements are precursors to vitamin D, which get converted in the body.

What is considered Vitamin D deficiency?
Deficiency is defined as levels less than 20 mg per ml of 25-hydroxy vitamin D. Levels between 20 to 30 indicate insufficiency and anything above 30 is considered normal.

Toxic levels are over 150 mg per ml and are exceedingly rare.

Deficiencies appear to be more common among African-Americans, due to high levels of melanin which block light from entering the skin. In addition levels are lower in the winter months (November through March) when less radiation reaches the earth. Levels are low in people living above 30 degree latitude, in cultures where the skin is covered (Arab countries) and in cultures where people avoid sunlight and use sunscreen.

Certain medical conditions make one more prone to deficiency such as individuals with bowel absorption problems, people with renal disease, obese individuals, vegetarians, people with lactose intolerance, and people on certain medications. (anticonvulsants)

What are the requirements for vitamin D in pregnant and lactating women?

Current research has shown that pregnant women are at high risk of vitamin D insufficiency and prenatal vitamins are inadequate in meeting these demands. Current vitamin preparations have approximately 200 to 400 IU of D. Experts recommend 1400—to 2000 IU of vitamin D per day in pregnancy. This can be accomplished with the regular prenatal vitamins in addition to another supplement. It has been suggested that breastfeeding women whose infants only get vitamin D from breast milk, need to ingest 4000 to 6000 IU of vitamin D per day.

Vitamin D levels should be obtained at the first prenatal visit along with the other prenatal blood work. If they are Vitamin D deficient, they should be treated with 2000IU f vitamin D in addition to their prenatal vitamins for 1-2 months and repeat the level to show that it is above 30ng/ml. With continued supplementation of 1000 IU of vitamin D per day, levels should be sufficient for the remainder of the pregnancy. Occasionally borderline individuals might need another level third trimester.

Ultraviolet light exposure can also increase the vitamin D content of human milk.

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Tags: morning sickness, nausea, pregnancy, vitamin D deficiency

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