Optimal Nutrition for Prevention of Hypertension in Pregnancy Using a Personalised Approach

The aim of this study is to investigate the role of the 677C→T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene on blood pressure (BP) during pregnancy, and to examine the effect of intervention with riboflavin, alone or in combination with 5-methyltetrahydrofolate (5-MTHF), as a non-drug approach for managing BP in pregnancy in women with the variant TT genotype. In addition, we aim to examine the effect of maternal supplementation with riboflavin, alone or combined with 5-MTHF, on BP in the offspring in early infancy.

Study design: A double-blind randomized controlled trial embedded in a large longitudinal observational study in pregnant women will be conducted. Women with a singleton pregnancy who are in their first trimester will be recruited from antenatal clinics in Northern Ireland and the Republic of Ireland. Women interested in the study will provide informed consent, complete a screening questionnaire and will provide a buccal swab to collect DNA to screen for the MTHFR 677C→T polymorphism. Women with multiple pregnancies, a previous NTD-affected pregnancy and those who are taking medication interfering with B-vitamin metabolism will be excluded from participation in the study. At approximately the 16th gestational week (GW), those with the variant TT genotype and age-matched heterozygous women (CT genotype) will be randomised to receive riboflavin (5 mg/day) alone, or in combination with 5-MTHF (400µg/day), or placebo, until the end of pregnancy. A non-fasting blood sample will be collected for biomarker assessment of B-vitamin status and other relevant variables from each participant before intervention and at the 36th GW. At the same time points, anthropometric and BP measurements will be taken. Women will also complete a health and lifestyle questionnaire and a 4-day dietary record. Samples of cord blood, umbilical cord and placenta will be collected after delivery and anthropometric parameters of the newborns will be retrieved postpartum. Maternal and infant BP will be measured 2-4 and 36 months after birth. In parallel with the intervention trial, age-matched pregnant women who do not carry the variant gene (CC genotype) and have not been randomized to treatment, will be monitored in order to control for any changes associated with normal pregnancy in the study outcome measurements. In the pilot phase, the feasibility and acceptability of the study procedures and treatment will be evaluated for clarification of the sample size and refinement of the study protocol.