This research project is now complete.
Why was this research needed?
Fetal growth restriction (FGR) is when a baby’s growth in the womb slows or stops, and affects around 5% of all pregnancies. Often when this happens, there isn’t enough blood flowing across the placenta, which means the baby can’t get the food and oxygen it needs to grow. Currently, there is no treatment for FGR: early delivery is the only option.
Our researchers are trying to change this, by trying to find ways to improve the blood flow to the placenta.
What happened in this project?
Nitric oxide is a small molecule made throughout the body that makes our blood vessels get wider, allowing blood to flow more easily. It is particularly important in making sure enough blood flows across the placenta during pregnancy. Having high blood pressure can reduce placental blood flow.
Nitrate is a nutrient which is abundant in green leafy vegetables and beetroot. Recently, scientists have shown that nitrate can be ‘activated’ in the body to increase levels of nitric oxide. Studies in non-pregnant humans and animals have shown that supplementing the diet with nitrate can increase blood flow and reduce blood pressure.
Researchers funded by Tommy’s and the British Heart Foundation have recently completed their study into the effects of beetroot juice, which has high levels of nitrate. In one part of the study, with pregnant mice with reduced placental blood flow, they demonstrated that beetroot juice can increase blood flow to the uterus.
In the other part of their study, pregnant women with high blood pressure were given either beetroot juice that contains nitrate, or a placebo (an identical juice with the nitrate removed). They found that nitrate supplementation significantly lowered blood pressure in some women, but not all. Importantly, amongst the 40 women that completed the trial, almost all said they would be willing to drink beetroot juice in the future if it would be of benefit.
What’s next for the study?
The results suggest that a dietary nitrate supplement could help to control blood pressure in pregnant women. However, further studies are now required to confirm this finding, and to understand why not all the women in the study benefitted from the beetroot juice supplement. We are now funding a new research project to understand whether bacteria present in the mouth may have a role to play in whether nitrate affects blood pressure.
Ultimately, these studies could provide an easy way for pregnant women to control high blood pressure, increasing blood flow to the placenta and reducing the risk of fetal growth restriction.
Ormesher L, Myers JE, Chmiel C, Wareing M, Greenwood SL, Tropea T, Lundberg JO, Weitzberg E, Nihlen C, Sibley CP, Johnstone ED, Cottrell EC. Effects of dietary nitrate supplementation, from beetroot juice, on blood pressure in hypertensive pregnant women: A randomised, double-blind, placebo-controlled feasibility trial. Nitric oxide: biology and chemistry. Nov 1 2018;80:37-44.
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