Changes in Central Arterial Pressure of Normotensive Women Taking Nifedipine for Tocolysis

Study Overview
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Brief Summary
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To determine the central blood pressure changes in normotensive women who are receiving nifedipine for uterine contraction suppression

Detailed Description
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Only women whom have been prescribed nifedipine tocolysis by their covering obstetrician will be approached to participate in the study. The patient will take their nifedipine as scheduled, we will attain central arterial pressure reading in addition to arterial waveform measurements. These will be collected: Before administration of the medication Every 20 minutes for 3 hours (total of 10 measurements) -This timing will allow measurements through approximately 2 half lives Routine sphygmomanometry will also be completed at the testing times All of these measurements will be collected for study purposes, although the nurses will have the opportunity to record the routine blood pressure measurements for their charting/vital signs assessment if they desire. Once the patient has been monitored for 3 hours, her participation in the study is considered complete and no additional information will be collected. Each patient will serve as her own control (blood pressure prior to administration of medication), no randomization will occur.

Official Title
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Changes in Central Arterial Pressure of Normotensive Women Taking Nifedipine for Tocolysis

Conditions
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Tocolysis With Nifedipine

Intervention / Treatment
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* Other: Nifedipine for tocolysis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Singleton pregnancy Currently receiving tocolysis with nifedipine (10 or 20mg q4-6 hours) Exclusion Criteria: Multiple pregnancy Diagnosis of hypertensive disorder in pregnancy or blood pressures 140/90 or higher on -more than 2 occasions. Currently on antihypertensive medications (Nifedipine XL, labetalol, hydralazine, methyl-dopa, etc) Currently on other tocolytic medications (exp: magnesium, Indocin) Narcotic use Renal diseaseI Irregular heart rhythms or arrhythmias Peripheral arterial disease, leg artery disease Reynaud's phenomena Intense cold/hypothermia If there is a wound at location of where central arterial cuff would be placed or tonometer for carotid assessment Severe tachycardia (>120) Greater than 1st degree heart block Severe asthma Congestive heart failure or heart disease Lupus, rheumatoid arthritis Inability to adequately monitor BP Magnesium treatment

Ages Eligible for Study
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Minimum Age: 14 Years
Maximum Age: 50 Years

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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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Nifedipine for tocolysis<br>Only women receiving nifedipine (as standard of care) for tocolysis | Other: Nifedipine for tocolysis<br>* observational<br>* Other names: Standard of care;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To determine the central blood pressure changes in normotensive women who are receiving nifedipine for tocolysis. | To determine the central blood pressure changes in normotensive women who are receiving nifedipine for tocolysis. | every 20 min for 3 hours |