Vascular responses to UV exposure in pregnancy
Research type
Research Study
Full title
UVA irradiation of skin in pregnant women increases uterine artery blood flow and reduces blood flow through a nitric oxide pathway
IRAS ID
170108
Contact name
Sarah Stock
Contact email
Clinicaltrials.gov Identifier
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
Season of birth influences pregnancy for reasons that remain unclear however the answer may lie in the amount of sunshine pregnant women are exposed to. Sunshine, or ultraviolet light (UV) exposure is known to have benefits on heart disease, strokes and depression. In pregnancy, relationships between sunshine exposure are evident in birth weight, preterm birth and blood pressure complications. Vitamin D, the UV generated hormone, was thought to be responsible when low levels were associated with these pregnancy complications. However, vitamin D replacement is ineffective at preventing these outcomes, and we hypothesise that it is the UV that is beneficial for pregnancy and it is working through a different pathway.
A new understanding of skin is central to this, with a 2014 study showing that exposing an adult to 20 minutes of low dose UV light lowered their blood pressure and improved blood flow. They demonstrated this was a direct effect of UV on the skin and was mediated by nitric oxide, a chemical central to many aspects of pregnancy including blood pressure regulation and uterine activity.
We have funding from Tommy’s - The Babies Charity to investigate if this effect is seen in pregnancy on the circulation. The design is similar to the previous method and volunteers would be recruited from clinical areas during the second trimester.
This pilot study would involve one visit and measurements taken would include heart rate, blood pressure, arteriography, ultrasound of the uterine arteries and blood measurements of nitric oxide levels. Arteriography is performed using a specialised arm cuff and is safe and non-invasive. An interventional control arm would be used to control other effects. A subset of these women would be invited to repeat this in the third trimester to investigate for a difference in effect at a later gestation.
REC name
South East Scotland REC 01
REC reference
15/SS/0115
Date of REC Opinion
20 Aug 2015
REC opinion
Further Information Favourable Opinion