A new study finds that women who develop a severe form of pregnancy-related high blood pressure tend to have lower blood levels of vitamin D. The condition is known as early-onset severe preeclampsia, and it contributes to about 15 percent of preterm births in the U.S. each year.
Researchers found that vitamin D levels were generally low among 50 women with early severe preeclampsia. Their average vitamin D level in the former group was a very low 18 nanograms per milliliter.