Vitamin D Deficiency may increase risk of Severe Pre-eclampsia

Reducing Risk of Pre-Eclampsia

New research has revealed that women who are deficient in vitamin D in the first 26 weeks of their pregnancy may be at risk of developing severe pre-eclampsia, a potentially life-threatening disorder.

In one of the largest studies to date, researchers from the University of Pittsburgh Graduate School of Public Health studied blood samples collected from 700 pregnant women who later developed pre-eclampsia, in an effort to examine a woman's vitamin D status during pregnancy and her risk of developing pre-eclampsia.

"For decades, vitamin D was known as a nutrient that was important only for bone health," said lead author Dr Lisa Bodnar, Associate Professor in the Department of Epidemiology.

 "Over the past 10 to 15 years, scientists have learned that vitamin D has diverse functions in the body beyond maintaining the skeleton, including actions that may be important for maintaining a healthy pregnancy."

Dr. Bodnar and her colleagues also studied blood samples from 3,000 mothers who did not develop pre-eclampsia. The samples were collected between 1959 and 1965 at 12 U.S. sites enrolled in the Collaborative Perinatal Project. The blood was well-preserved, and researchers were able to test for vitamin D levels decades later.

Scientists controlled for factors that could have affected a woman's vitamin D status, including race, pre-pregnancy body mass index, number of previous pregnancies, smoking, diet, physical activity and sunlight exposure, which is the body's primary source of vitamin D.

The researchers found that vitamin D sufficiency was associated with a 40 percent reduction in risk of severe pre-eclampsia. But there was no relationship between vitamin D and mild pre-eclampsia. The overall risk of severe pre-eclampsia in the women sampled was 0.6 percent, regardless of vitamin D status.

"Scientists believe that severe pre-eclampsia and mild pre-eclampsia have different root causes," said senior author Dr Mark A. Klebanoff. "Severe pre-eclampsia poses much higher health risks to the mother and child, so linking it with a factor that we can easily treat, like vitamin D deficiency, holds great potential."

"If our results hold true in a modern sample of pregnant women, then further exploring the role of vitamin D in reducing the risk of pre-eclampsia would be warranted," said Dr. Bodnar. "Until then, women shouldn't automatically take vitamin D supplements during pregnancy as a result of these findings."

Commenting on the findings of the study, leading Consultant Obstetrician Mr Ashok Kumar said: “Pre-eclampsia is a complicated condition that affects up to 10% of pregnancies. Although most cases are fortunately quite mild, severe pre-eclampsia can cause very serious problems for both mother and baby. I will be very interested to see if further studies into the role of Vitamin D during pregnancy back up the findings of this new research as taking additional vitamins is a simple thing for pregnant women to do in order to reduce the risk of pre-eclampsia.”

The study is available online in the journal Epidemiology.

A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
A measure of whether a person’s weight is normal, too high or too low. It is calculated by dividing their weight in kilograms by the square of their height in metres. Full medical glossary
A serious disease occurring in late pregnancy causing seizures and sometimes coma. It usually follows pre-eclampsia. Full medical glossary
A condition of pregnancy associated with high blood pressure and protein in the urine (proteinuria). Full medical glossary
the period from conception to birth Full medical glossary
Essential substances that cannot be produced by the body and so must be acquired from the diet. Full medical glossary