Vascular Responses to UV Exposure in Pregnancy

NCT02482363 | Completed

• 1 other identifier: 170108
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief 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 already known to have benefits for health on heart disease, strokes and depression. In pregnancy, relationships between sunshine exposure are evident in birth weight, preterm birth and risk of blood pressure complications. Vitamin D, the UV generated hormone, was thought to be responsible when low vitamin D levels were associated with these pregnancy complications. However, vitamin D replacement is ineffective at preventing these outcomes, and the investigators hypothesise that this is because it is the UV that is beneficial for pregnancy and it is working through a different pathway. A new understanding of skin function 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. These investigators 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. The investigators in this study have funding from Tommy's to investigate if a similar effect is seen in pregnancy on the circulation. The design is similar to the previously successful method and volunteers would be recruited from clinical areas during the second trimester. As both resting and warming for 20 minutes have the potential to have similar effects on the circulation, a control arm will expose participants to these without the UV. 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. 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.

Conditions

Pregnancy

Outcome Measures

Primary Outcomes (1)

• Uterine artery Doppler

  The uterine artery will be interrogated with abdominal ultrasound to determine diameter and Doppler measurements to calculate resistance indices (PI) and flow velocity. This will be done at baseline and at 10 minutely intervals following exposure for 60 minutes.

  Change over 60 minutes following exposure

Secondary Outcomes (3)

• Blood pressure

  60 minutes

• Nitrospecies

  60 minutes

• Arteriography

  60 minutes

Study Arms (2)

Active UVA radiation

ACTIVE COMPARATOR

This arm will receive 20 minutes of UVA to the skin while resting quietly.

Radiation: UVA radiation

Sham control

SHAM COMPARATOR

This arm will receive 20 minutes of quiet rest and heat but with their skin protected from UVA

Radiation: Sham Control

Interventions

UVA radiation RADIATION

20 minutes of low dose UVA from a phototherapy unit

Active UVA radiation

Sham Control RADIATION

20 minutes of sham control exposure

Sham control

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Pregnant volunteers
• Ages 18- - 45
• No significant medical or obstetric history
• English speaking
• Able to provide informed consent
• Singleton pregnancy
• Low risk first trimester screen
• Have 4 hours of time
• Historical risk factors for growth restriction or pre-eclampsia
• Papp A \< 0.40 MoMs

You may not qualify if:

• Non english speaking
• Smoking
• History of intrauterine growth restriction (IUGR) or pre-eclampsia
• BMI \>40
• Contraindication to UV exposure
• History of blood born viruses (hepatitis B, C, HIV)

Sponsors & Collaborators

• University of Edinburgh: lead
• NHS Lothian: collaborator

Study Sites (1)

NHS Lothian

Edinburgh, EH16 4TJ, United Kingdom

Location

Study Officials

• SARAH STOCK, BSc MBChB

  QUEEN'S MEDICAL RESEARCH INSTITUTE

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: SINGLE
• Who Masked: INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 12, 2015
• First Posted: June 26, 2015
• Study Start: September 1, 2015
• Primary Completion: March 31, 2016
• Study Completion: March 31, 2016
• Last Updated: May 21, 2024

Record last verified: 2024-05

Locations

GB (1)