NCT05434195Recruiting
Clinical Antenatal Randomised Study to CharactErise Key Roles of TetrahydroFOLate in HyperTensive Pregnancies
Clinical Antenatal Randomised Study to CharactErise Key Roles of TetrahydroFOLate in HyperTensive Pregnancies (CAREFOL-HT)
Source: ClinicalTrials.gov · Last updated 29 Apr 2026
Brief summary (registry, in English)
Study background High blood pressure during pregnancy is a worldwide health problem that can be dangerous to mothers and commonly causes premature birth and small babies. There is also growing evidence that mothers who suffer from high blood pressure in pregnancy, and their babies, have a higher risk of high blood pressure and cardiovascular disease later in life. Previous studies have revealed detrimental changes in the structure and function of the heart and blood vessels of mothers, and their babies, who experience this common complication. These changes may explain their increased risk of later disease. The investigators have also learned through previous studies that tetrahydrobiopterin (BH4), a molecule that has a role in blood vessel health, plays an important role in stabilising blood vessel function. Lower levels of BH4 are evident in both the placenta and the umbilical cord from mothers with high blood pressure. We, therefore, want to investigate how closely BH4 levels are related to clinical features of pre-eclampsia and whether altering levels of BH4, using a nutritional supplement, improves features of the disease such as blood vessel function. To do this, the investigators need to compare the levels of BH4 between mothers with pre-eclampsia, those taking the supplement and those without pre-eclampsia. The investigators also compare how the heart and blood vessels look and function in these groups using ultrasound methods, including echocardiography and fetal sonography. Study objectives CAREFOL-HT will assess how levels of BH4 differ in pregnant women with high blood pressure and if this is reflected in functional changes in the heart and blood vessels of these women. The investigators will also determine whether changing levels of BH4, using a tetrahydrofolate supplement (5-MTHF), changes blood vessel function.
- Status (registry)
- Recruiting
- Study type
- Interventional
- Enrollment
- 128 (estimated)
- First submitted
- 5 May 2022
- Start date
- 1 Jun 2021
- Primary completion date
- 1 Jan 2026
- Lead sponsor
- University of Oxford
- Diseases
- High blood pressure
- NCT number
- NCT05434195
What you commit to
- Study type: Interventional
- Planned participants: 128
- From 1 Jun 2021 to the primary completion date, 1 Jan 2026
- 2 sites in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Intake of either proton pump inhibitors or anti-epileptic drugs
Other illness
- History of cardiac impairments including uncontrolled arrhythmia, unstable angina, decompensated congestive heart failure or valve disease
- History of preexisting chronic renal disease
- Fetus with congenital heart defect
- Fetus at a high risk of heart disease
- Known infection of fetus
- Diagnosis of hypertensive disorder of pregnancy
- History of cardiac impairments including uncontrolled arrhythmia, unstable angina, decompensated congestive heart failure or valve disease
- History of preexisting chronic renal disease Fetal
- Fetus with congenital heart defect
- Fetus at a high risk of heart disease
- Known infection of fetus
Other
- The participant may not enter the study if ANY of the following apply:
- Maternal
- Contraindication to taking folate related supplements
- Folate supplementation in excess of 400mcg in the third trimester
- Low vitamin B12 levels (\<148 pmol/L)
- Organ dysfunction Fetal
- Any known trisomy
- Known severe anaemia
- The participant may not enter the study if ANY of the following apply:
- Maternal
- Use of beta blockers such as atenolol or equivalent
- Any known trisomy
- Known severe anaemia
Who the study is looking for
- 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
- 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
Age in the registry: 18 years to 45 years · Sex: Female · Accepts healthy volunteers
Sites (2)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Cardiovascular Clinical Research Facility Coordinator of this site? Confirm its status | Oxford | United Kingdom | Recruiting |
| Oxford University Hospitals NHS Foundation Trust Coordinator of this site? Confirm its status | Oxford | United Kingdom | Recruiting |
Related publications
- Retinal Vascular Caliber: 6 to 12 Months and 15 to 25 Years Following Hypertensive Pregnancy.Hypertension · 2026 · PMID 42305089
This page is information, not medical advice. Discuss any trial with your doctor.