Marinobufagenin as a Target for DIGIBIND in Preeclampsia

Background: * Preeclampsia is a combination of high blood pressure and other potentially life-threatening symptoms. Preeclampsia occurs in up to 10% of pregnancies and is a main cause of maternal and fetal death worldwide. Treatment is often difficult, and so far there is no specific and effective therapy. Researchers have been studying the body systems that regulate blood pressure. They have also studied drugs that can control certain blood chemicals that constrict blood vessels and increase blood pressure. * DIGIBIND, a drug that lowers blood pressure, has been used to treat pre-eclampsia. Marinobufagenin (MBG), a chemical in the blood that constricts blood vessels, has been shown to be involved in pre-eclampsia. But researchers are still not certain whether DIGIBIND can be used to specifically target MBG. Researchers want to find out whether DIGIBIND acts against MBG specifically. This information may help them to develop better drugs to block MBG and lower blood pressure in women with preeclampsia. Objectives: \- To study whether the blood pressure treatment drug DIGIBIND specifically acts on marinobufagenin levels in the blood of pregnant women. Eligibility: \- Women between 18 and 50 years of age who are 34 to 39 weeks pregnant and have preeclampsia. Design: * Participants will be screened with a physical examination, medical history, and blood and urine tests. * Before delivery, participants will provide blood samples for testing and evaluation. * Following delivery, participants will provide additional blood samples and samples of the placenta for testing and evaluation. * No additional treatment, apart from the standard of care, will be provided as part of this protocol.