Researchers found that the children of women with preeclampsia had higher systolic blood pressure on average.
Although earlier research has found that children have an increased risk of high blood pressure when born to a mother with preeclampsia, new evidence suggests that this adverse association may be reduced, or even eliminated, for children exposed to higher levels of vitamin D in the womb.
The findings are based on a data analysis by Johns Hopkins Bloomberg School of Public Health of 754 mother-child pairs in Massachusetts, examining how higher levels of vitamin D in pregnancy can impact children’s blood pressure. High blood pressure during childhood has also been associated with hypertension and heart disease in adulthood.
Preeclampsia, which can lead to strokes and organ failure, is a major cause of illness and death for pregnant women. It has also been associated with a greater risk of stillbirth and preterm birth.
Preeclampsia is estimated to occur in 2% to 8% of pregnancies worldwide, though rates of severe preeclampsia in the United States have risen sharply since the 1980s. Simultaneously, rates of high blood pressure among American children rose by approximately 40% between 1988 and 2008, with studies suggesting that maternal preeclampsia may be a contributing factor.
“We wanted to know if vitamin D levels in the womb would modify this association between maternal preeclampsia and hypertension in childhood,” said first study author Mingyu Zhang in a press release.
To investigate, researchers conducted a large epidemiological study using data from the 754 mother-child pairs. The dataset included information on preeclampsia during pregnancy, blood tests from the umbilical cord at birth, and the children’s blood pressure from ages 3 to 18.
According to a press release, approximately 62% of the mothers were Black and 52% were overweight or obese. Earlier studies have suggested that Black or overweight mothers were at higher risk for preeclampsia.
Approximately 10% of the women studied had preeclampsia, and the analysis found that their children, on average, had higher systolic blood pressure than the children born to non-preeclamptic mothers. Specifically, their blood pressure was approximately 5 percentile points higher when all the blood pressure readings were arranged on a 0 to 100 percentile scale.
Vitamin D levels in the umbilical cord clearly modified these associations, according to a press release. Children in the lowest quartile of vitamin D levels were approximately 11 percentile points higher in blood pressure, on average, if their mothers had preeclampsia.
For children in the highest quartile, researchers said there appeared to be no difference in average blood pressure if their mothers had preeclampsia.
“There is increasing evidence that cardiovascular disease risk is, to a great extent, programmed in the womb, and we now see that it may be vitamin D that alters this programming in a beneficial fashion,” said senior author Noel Mueller, PhD, in the press release.
Exposure to Vitamin D in the Womb Might Minimize Risk of High Blood Pressure for Children Born to Mothers with Preeclampsia [news release]. Johns Hopkins Bloomberg School of Public Health; October 5, 2020. https://www.jhsph.edu/news/news-releases/2020/exposure-to-vitamin-d-in-the-womb-might-minimize-risk-of-high-blood-pressure-for-children-born-to-mothers-with-preeclampsia.html. Accessed October 7, 2020.