Dietary Salt During Pregnancy and Maternal Vascular Function

Study Overview
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Brief Summary
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The main goal of this study is to investigate the association of dietary salt intake during pregnancy with systemic micro- and macrovascular reactivity and uteroplacental vascular function of the mother, and to examine the potential impact of elevated oxidative stress on this association. Also, the aim is to investigate whether there is an association between excessive salt intake during pregnancy and the outcome of pregnancy.

Detailed Description
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During the study pregnant women at the third trimester of pregnancy (37-38 weeks of pregnancy) will have one study visit during which following procedures will be done: measurement of maternal systemic microvascular function by Laser Doppler flowmetry (post-occlusive reactive hyperemia, iontophoresis of acetylcholine and sodium nitroprusside) measurement of maternal systemic macrovascular function by vascular ultrasound measurement of brachial artery flow mediated dilation (FMD) measurement of maternal uteroplacental function by ultrasound color Doppler measurement of umbilical artery and fetal middle cerebral artery blood flow venous blood sampling; serum will be stored for measurement of oxidative stress, matrix metalloproteinase 9 and endocan level 24-hour urine natriuresis (to estimate daily salt intake) measurement of blood pressure, heart rate, height and weight, body composition Immediately after the childbirth following procedures will be done: assessment of pregnancy outcome (duration of pregnancy, child birth weight, child birth length and Apgar score) placental tissue will be taken and stored for measurement of matrix metalloproteinase 9

Official Title
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Influence of Dietary Salt Intake During Pregnancy on Maternal Systemic and Uteroplacental Vascular Function

Conditions
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Salt; Excess, Pregnancy Related

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy pregnant women in the third trimester of pregnancy (37-38 weeks of pregnancy) Exclusion Criteria: smoking prenatal hypertension thrombophilia low molecular weight heparin use coronary heart disease preconception diabetes gestational diabetes renal impairment cerebrovascular and peripheral artery disease any other preconception disease that could affect vascular and endothelial function
Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Low-salt (LS) group<br>intake of < 5 g of salt per day | |
| Normal-salt (NS) group<br>intake of 5 - 7.5 g of salt per day | |
| High-salt (HS) group<br>intake of 7.5 - 10 g of salt per day | |
| Very high-salt (VHS) group<br>intake of > 10 g of salt per day | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maternal systemic microvascular function | Skin microvascular reactivity assessed by Laser Doppler flowmetry (post-occlusive reactive hyperemia, iontophoresis of acetylcholine and sodium nitroprusside) - measured in perfusion units (PU) | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 
| Maternal systemic macrovascular function | Vascular ultrasound measurement of brachial artery flow mediated dilation (FMD) | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 
| Maternal uteroplacental function | Ultrasound color Doppler measurement of umbilical artery and fetal middle cerebral artery blood flow | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxidative stress - thiobarbituric acid reactive substances (TBARS) | Measurement of biomarkers of oxidative stress level. Thiobarbituric acid reactive substances (TBARS) - biomarker of lipid peroxidation. | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 
| Matrix metalloproteinase 9 | ELISA measurement of serum matrix metalloproteinase 9 level in mother serum and placental tissue sample (taken after childbirth) | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) (serum) and immediately after childbirth (placental tissue sample) | 
| Endocan | ELISA measurement of serum endocan level - proteoglycan associated with endothelium activation | at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 
| Pregnancy outcome - duration | Duration of pregnancy (weeks and days) | the outcome measure will be assessed at one time point in the third trimester of pregnancy (37-38 weeks of pregnancy) | 
| Pregnancy outcome - birth weight | Birth weight (in grams) | at one time point immediately after childbirth | 
| Pregnancy outcome - birth length | Birth length (in cm) | at one time point immediately after childbirth | 
| Pregnancy outcome - Apgar score | Apgar score (in Apgar score scale, a total score of 1 to 10; the higher the score, the better the baby is doing after birth) | at one time point immediately after childbirth | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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salt intake, microcirculation, macrocirculation, endothelium, uteroplacental function, pregnancy, oxidative stress