Women with a history of high blood pressure have changes in the way their blood vessels work compared to women with normal pregnancies. During pregnancy, the blood flow around the body is higher because of the extra needs of the baby. Usually, women adapt to this – their blood vessels relax so that blood can pass through them more easily. In women with chronic hypertension, this doesn’t happen. This can make it more likely for women to suffer from pre-eclampsia, or for their babies to be growth restricted.
A study in the Manchester Antenatal Vascular Service (MAViS) is using a sensitive blood pressure machine to measure the stiffness of blood vessels in pregnant women. We already know that this is a much more accurate way of looking at high blood pressure in people who aren’t pregnant.
So far, over 280 women are taking part in the study. The results so far already show that measuring blood vessel stiffness in early pregnancy helps doctors to tell which women are at risk of needing early delivery. Using both measurements of blood vessel stiffness and ultrasound scans, researchers found 80% of the women who would need early delivery.
Going forward, women who are found to be at risk of needing early delivery will take part in CHERRY – the CHronic hypERtension and L-citRulline studY. This is a randomised control trial that will test the effectiveness of a drug called L-citrulline, that helps lower blood pressure.
Helping women with chronic hypertension during pregnancy is vital: the earlier doctors know who is at risk, the better they can plan for the safe and healthy delivery of the baby. There are also big economic pluses: even a 10% drop in early deliveries would save UK neonatal units around £4.2 million every year.
This study takes place in a Tommy's centre and is funded by the National Institute for Health ResearchHide details