None listed
Conditions
Brief summary
Flow-mediated dilation is a non-invasive procedure that can determine whether blood vessels have dysfunction. Normally, this technique involves preventing/occluding blood flow from the lower arm to the hand for a period of 5 minutes, then using ultrasound to determine how well the brachial (arm) artery relaxes after blood flow resumes. However, this method was established in non-pregnant participants and has been translated in pregnancy without confirming how long the occlusion period needs to be. Therefore, participants will have flow-mediated dilation performed on their brachial artery two times; once after a 3 minute occlusion and once after a 5 minute occlusion. Additionally, an ophthalmic artery Doppler will also be performed. This will occur over a ~2 hour period on the same day.
Interventions
This is an observational study that examines non-invasive vascular assessment methods during pregnancy. The exposure of interest is pregnancy, and the study aims to assess maternal vascular function using two ultrasound-based techniques.
During a single study visit lasting approximately 2 hours, participants will undergo all assessments on the same day. Flow-mediated dilation (FMD) of the brachial artery will be performed twice by trained research staff using ultrasound. A blood pressure cuff p
This is an observational study that examines non-invasive vascular assessment methods during pregnancy. The exposure of interest is pregnancy, and the study aims to assess maternal vascular function using two ultrasound-based techniques. During a single study visit lasting approximately 2 hours, participants will undergo all assessments on the same day. Flow-mediated dilation (FMD) of the brachial artery will be performed twice by trained research staff using ultrasound. A blood pressure cuff placed on the forearm will be inflated to temporarily occlude blood flow to the hand, once for 3 minutes and once for 5 minutes, with ultrasound used to measure the artery’s response after cuff release. Participants will also undergo ophthalmic artery Doppler ultrasound, performed by trained study personnel, using an ultrasound probe placed gently over the closed eyelid to assess blood flow in the ophthalmic artery. Following completion of the visit, participants will be emailed a brief survey, taking approximately 10 minutes, to obtain their perspectives on the procedures used in the study.
Sponsors
Monash Health
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Healthy, pregnant women: • Singleton pregnancy. • greater than or equal to 18 years of age • Gestation between 11+0 and 14+0 weeks pregnant, 20+0 and 28+0 weeks pregnant, or 29+0 and 40+0 weeks pregnant. • Body mass index (BMI) between 18 – 35kg/m2. • Normal mid-trimester morphology scan, with no detectable significant anomalies (where relevant). • Estimated fetal weight between 3rd and 99th centile • Deemed capable of understanding the information provided and able to give written informed consent (with interpreter use as required).
Exclusion criteria
• Nil major complications of pregnancy including but not limited to: o Hypertension or a history of hypertension. o Pre-existing cardiovascular disease. o Pre-gestational diabetes or gestational diabetes. o Body mass index (BMI) >35kg/m2. o Fetal growth restriction estimated fetal weight 95th), absent end-diastolic flow or reversal of end-diastolic flow reduced middle cerebral artery pulsatility index (MCA PI <5th) or abnormal ductus venosus (DV). • Significant uncertainty in ensuring gestational age is within limits • Unwillingness or inability to follow the procedures outlined in the PICF. • Current smoking/vaping or nicotine replacement. • Vasoactive medications (e.g., nitrates, PDE-5 inhibitors) • Active ophthalmic disease/procedures. • Mentally, cognitively, or legally incapacitated or ineligible to provide informed consent. • Co-recruitment/participation in a clinical trial where there is an intervention that affects cardiovascular function.
Outcome results
None listed