Effects of dietary nitrate supplementation, from beetroot juice, on blood pressure in hypertensive pregnant women: A randomised, double-blind, placebo-controlled feasibility trial.

Chronic hypertension in pregnancy is associated with significant adverse pregnancy outcomes, increasing the risk of pre-eclampsia, fetal growth restriction and preterm birth. Dietary nitrate, abundant in green leafy vegetables and beetroot, is reduced in vivo to nitrite and subsequently nitric oxide, and has been demonstrated to lower blood pressure, improve vascular compliance and enhance blood flow in non-pregnant humans and animals. The primary aims of this study were to determine the acceptability and efficacy of dietary nitrate supplementation, in the form of beetroot juice, to lower blood pressure in hypertensive pregnant women. In this double-blind, placebo-controlled feasibility trial, 40 pregnant women received either daily nitrate supplementation (70 mL beetroot juice, n = 20) or placebo (70 mL nitrate-depleted beetroot juice, n = 20) for 8 days. Blood pressure, cardiovascular function and uteroplacental blood flow was assessed at baseline and following acute (3 h) and prolonged (8 days) supplementation. Plasma and salivary samples were collected for analysis of nitrate and nitrite concentrations and acceptability of this dietary intervention was assessed based on questionnaire feedback. Dietary nitrate significantly increased plasma and salivary nitrate/nitrite concentrations compared with placebo juice (p < 0.001), with marked variation between women. Compared with placebo, there was no overall reduction in blood pressure in the nitrate-treated group; however there was a highly significant correlation between changes in plasma nitrite concentrations and changes in diastolic blood pressure in the nitrate-treated arm only (r = -0.6481; p = 0.0042). Beetroot juice supplementation was an acceptable dietary intervention to 97% of women. This trial confirms acceptability and potential efficacy of dietary nitrate supplementation in pregnant women. Conversion of nitrate to nitrite critically involves oral bacterial nitrate reductase activities. We speculate that differences in efficacy of nitrate supplementation relate to differences in the oral microbiome, which will be investigated in future studies.

CHronic hypERtension and L-citRulline studY (CHERRY): an Early-Phase Randomised Controlled Trial in Pregnancy.

Oral supplementation with L-citrulline, which is sequentially converted to L-arginine then nitric oxide, improves vascular biomarkers and reduces blood pressure in non-pregnant, hypertensive human cohorts and pregnant mice with a pre-eclampsia-like syndrome. This early-phase randomised feasibility trial assessed the acceptability of L-citrulline supplementation to pregnant women with chronic hypertension and its effects on maternal BP and other vascular outcomes. Pregnant women with chronic hypertension were randomised at 12-16 weeks to receive 3-g L-citrulline twice daily (n = 24) or placebo (n = 12) for 8 weeks. Pregnant women reported high acceptability of oral L-citrulline. Treatment increased maternal plasma levels of citrulline, arginine and the arginine:asymmetric dimethylarginine ratio, particularly in women reporting good compliance. L-citrulline had no effect on diastolic BP (L-citrulline: - 1.82 95% CI (- 5.86, 2.22) vs placebo: - 5.00 95% CI (- 12.76, 2.76)), uterine artery Doppler or angiogenic biomarkers. Although there was no effect on BP, retrospectively, this study was underpowered to detect BP changes < 9 mmHg, limiting the conclusions about biological effects. The increase in arginine:asymmetric dimethylarginine ratio was less than in non-pregnant populations, which likely reflects altered pharmacokinetics of pregnancy, and further pharmacokinetic assessment of L-citrulline in pregnancy is advised.Trial Registration EudraCT 2015-005792-25 (2017-12-22) and ISRCTN12695929 (2018-09-20).

The design of a community lifestyle programme to improve the physical and psychological well-being of pregnant women with a BMI of 30 kg/m2 or more.

BACKGROUND: Obesity is a global public health issue. Having a BMI of 30 kg/m2 or more (classifying a person as obese) at the start of pregnancy is a significant risk factor for maternal and fetal morbidity. There is a dearth of evidence to inform suitable interventions to support pregnant women with a BMI of 30 kg/m2 or more. Here we describe a study protocol to test the feasibility of a variety of potential healthy lifestyle interventions for pregnant women with a BMI of 30 kg/m2 or more in a community based programme. METHODS/DESIGN: Four hundred women will be approached to attend a 10-week community lifestyle programme. The programme will be provided as a supplement to standard antenatal care. The programme is multi-faceted, aimed at equipping participants with the skills and knowledge needed to adopt healthy behaviours. The social (cognitive) learning theory will be used as a tool to encourage behaviour change, the behaviour change techniques are underpinned by five theoretical components; self-efficacy, outcome expectancies, goal setting, feedback and positive reinforcement.The main outcomes are pregnancy weight gain and caesarean section rate. Other important outcomes include clinical outcomes (e.g., birth weight) and psychological outcomes (e.g., well-being). Secondary outcomes include women's experience of pregnancy and health care services, amount of physical activity, food intake and the suitability of the intervention components.A prospective study using quantitative and qualitative methods will inform the feasibility of implementing the community lifestyle programme with pregnant women with a BMI of 30 kg/m2 or more. Mixed methods of data collection will be used, including diaries, focus groups/interviews, pedometers, validated and specifically designed questionnaires, a programme register, weight gain during pregnancy and perinatal outcome data. DISCUSSION: Findings from this current feasibility study will inform future interventions and NHS services and add to the evidence-base by providing information about the experiences of pregnant women with a BMI of 30 kg/m2 or more undertaking a community lifestyle programme. The study will lead on to a randomised control trial of a suitable intervention to improve the pregnancy outcomes of this target group.