Vitamin D in Pregnancy May Prevent High Blood Pressure in Children

High blood pressure in pregnancy is called preeclampsia. Up to eight percent of pregnant women get preeclampsia. Although it can usually be managed, it is still the leading cause of pregnancy complications.

Preeclampsia has been increasing in recent years. Since the 1980s, preeclampsia is up about 25 percent. Another problem that has been increasing over the same time is high blood pressure in children. Although you may not associate children with high blood pressure, it has actually increased by about 40 percent.

Children with high blood pressure tend to grow up into adults with high blood pressure and that means a higher risk for stroke and heart disease. Research shows that there is a link between preeclampsia and high blood pressure in children. If you have preeclampsia, your child will be at higher risk for hypertension.

Research also shows that preeclampsia may be linked to vitamin D. Low levels of vitamin D during pregnancy increase your risk of preeclampsia. That brings us to an important new study from researchers at Johns Hopkins University School of Public Health. They found that  higher levels of vitamin D for babies in the womb reduces the risk of developing childhood high blood pressure.

Since vitamin D may reduce the risk of preeclampsia, the researchers wanted to know if low vitamin D levels in pregnant women with preeclampsia would show up as high blood pressure in their babies over time, since they would receive less vitamin D inside the womb.

The researchers took advantage of a pregnancy study called the Boston Birth Cohort, which has been collecting heath data on pregnant mothers and their children since 1998. Located at Boston Medical Center, the data includes key information the researchers needed to test their theory.

They looked at data from 754 mother-child pairs that included baby vitamin D levels from umbilical cord blood (which told them how much vitamin D the baby was getting in the womb from the mother), diagnosis of preeclampsia in the mothers, and blood pressure measurements of the children from ages 3 through 18.

Their findings are published in JAMA Network Open. These are the key findings:

  • Of the mothers, about 10 percent were diagnosed with preeclampsia. This was a slightly higher rate than usual. One explanation is that over 50 percent of women in the study were obese or overweight, which is a risk factor for preeclampsia.
  • Children who were born to mothers diagnosed with preeclampsia had and average of five percent higher blood pressure numbers than children of women who did not have preeclampsia.
  • Vitamin D cord levels of the children confirmed a link between vitamin D and high blood pressure. Children in the lowest 25 percent of vitamin D levels had an average of 11 percent higher blood pressure numbers than children of mothers without preeclampsia. Children in the highest 25 percent had the same average blood pressures as children of mothers without preeclampsia.

The researchers conclude that increasing vitamin D levels in pregnant women may reduce the risk of mothers with preeclampsia giving birth to babies who develop high blood pressure during childhood. The researchers would like to have their findings confirmed by future studies.

According to the American College of Obstetricians and Gynecologists (ACOG), vitamin D deficiency is common in pregnant women. Vitamin D is found in prenatal vitamins, but the usual amount is 400 international units (IUs). ACOG says that a pregnant woman who is vitamin D deficient may need from 1 to 2,000 IUs to get into a safe level.

Based on this study, it makes sense to talk to your pregnancy care provider about your vitamin D level, especially if you have risk factors for preeclampsia like being overweight, having a previous history of high blood pressure, being African American, or being pregnant in your teens or over age 35. Carrying twins or multiples and having a family history of preeclampsia are also risk factors. A discussion about vitamin D could help prevent high blood pressure for you and your baby.

Christopher Iliades
Dr. Chris Iliades is a medical doctor with 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, and The Johns Hopkins Children's Center Magazine. Chris lives with his wife and close to his three children and four grandchildren in the Boston area.

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