Could a simple vitamin help pregnant women with high blood pressure?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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