Clinical Antenatal Randomised Study to CharactErise Key Roles of TetrahydroFOLate in HyperTensive Pregnancies

Inclusion Criteria (Preeclampsia individuals): * Diagnosed with preeclampsia, as defined in Section 8.1, at \<34 weeks' gestation within the last 48 hours and with no delivery planned within the next week * Receiving antenatal care in the John Radcliffe Hospital * Participant is willing and able to give informed consent for participation in the study * Age \>18 and ≤45 years Exclusion Criteria (Preeclampsia individuals): The participant may not enter the study if ANY of the following apply: Maternal * History of cardiac impairments including uncontrolled arrhythmia, unstable angina, decompensated congestive heart failure or valve disease * History of preexisting chronic renal disease * Contraindication to taking folate related supplements * Folate supplementation in excess of 400mcg in the third trimester * Low vitamin B12 levels (\<148 pmol/L) * Intake of either proton pump inhibitors or anti-epileptic drugs * Organ dysfunction Fetal * Any known trisomy * Fetus with congenital heart defect * Fetus at a high risk of heart disease * Known infection of fetus * Known severe anaemia Inclusion Criteria (Normotensive individuals): * Participant is willing and able to give informed consent for participation in the study * Age \>18 and ≤45 years * Normotensive, blood pressures \<140/90 throughout antenatal period * Less than 2 moderate risk factors for hypertensive disease in pregnancy according to the NICE guideline for management of hypertension in pregnancy * SFlt/PIGF ratio \<35 Exclusion Criteria (Normotensive individuals): The participant may not enter the study if ANY of the following apply: Maternal * Diagnosis of hypertensive disorder of pregnancy * Use of beta blockers such as atenolol or equivalent * History of cardiac impairments including uncontrolled arrhythmia, unstable angina, decompensated congestive heart failure or valve disease * History of preexisting chronic renal disease Fetal * Any known trisomy * Fetus with congenital heart defect * Fetus at a high risk of heart disease * Known infection of fetus * Known severe anaemia