Cardiovascular Research in EMbarazo and MAternity (EMMA). Study on Heart Rate Variability and Hemodynamic Adaptations During Pregnancy and Postpartum. (EMMA)

Heart rate variability (HRV) provides a non-invasive assessment of autonomic control of the nervous system over the heart. During pregnancy, the cardiovascular system adapts significantly, affecting HRV and hemodynamics. Studying the relationship between HRV and hemodynamic changes is critical to understanding and monitoring cardiovascular health during pregnancy and postpartum, and predicting potential complications.

Study Overview

• Status: Recruiting
• Conditions: Pregnancy Related; Hemodynamics; Heart Rate Variation (HRV)
• Intervention / Treatment: Other: Assessment of HRV and blood pressure

• Study Type: Observational
• Enrollment (Estimated): 242

Contacts and Locations

• Study Contact: Name: Alicia González Represas; Phone Number: 616044977; Email: alicia@uvigo.gal

Study Locations

• Spain
  • Pontevedra
    • Vigo, Pontevedra, Spain, 36312
      • Recruiting
      • Hospital Alvaro Cunqueiro
      • Contact: Emilio Couceiro Naveira
      • Contact: Email: Emilio.Couceiro.Naveira@sergas.es

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Women pregnant from the first trimester of gestation over 18 years.

Description

Inclusion Criteria:

• Over 18 years of age
• Pregnancy from the third month of gestation
• No pre-existing cardiovascular disease
• Good cognitive level
• Sign informed consent

Exclusion Criteria:

• Diabetes mellitus
• Hyperthyroidism
• Hypothyroidism
• Chronic hypertension diagnosed before pregnancy
• Heart failure
• Ischemic heart disease or malignant ventricular arrhythmias (ventricular fibrillation, ventricular tachycardia, grade 2 or 3 AV block, atrial fibrillation in patients with Wolff-Parkinson- White syndrome, paroxysmal fibrillation or flutter with rapid ventricular response and hemodynamic deterioration, uncontrolled supraventricular tachycardia)
• Exercise-induced ischaemia
• Unstable angina
• Disease not susceptible to revascularization
• Associated valvular heart disease
• Chronic kidney disease
• Degenerative neurological condition
• Brain aneurysms
• Arteriovenous malformations
• History of transient cerebral infarction (ICTUS)
• Migraines diagnosed
• Epilepsy
• Brain or spinal cord injury
• Tumors
• Diseases of the respiratory tract
• Diseases of lung tissue
• Diseases of pulmonary circulation

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Unic group	Other: Assessment of HRV and blood pressure; Assessment of Heart Rate Variation (HRV) and blood pressure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
RR (R-R range)	The RR interval is the time between successive R-waves of the QRS complex now electrocardiogram (ECG) expressed in milliseconds (ms). It is a fundamental unit in HRV analysis and represents the time between two consecutive heartbeats.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
RMSSD (Root Mean Square of Successive Differences)	RMSSD is a measure in the tempo domain that quantifies variability in the length of consecutive RR intervals expressed in milliseconds (ms). It reflects short-term HRV and is influenced by the parasympathetic nervous system.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
pNN50 (Percentage of successive RR intervals differing by more than 50 ms)	pNN50 is another measure in the time domain that represents a percentage (%) of RR intervals that differ by more than 50 ms. It is also indicative of short-term HRV and is related to parasympathetic activity.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
HF (High Frecuency)	HF is a measurement in the frequency domain that represents the power of heart rate variability in the high frequency range (typically 0.15 to 0.4 Hz). It is associated with parasympathetic (vagal) activity and is often analyzed by spectral analysis of the HRV signal. Expressed in milliseconds squared (ms^2).	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
LF (low frequency)	LF is a measurement in the frequency domain that represents the power of heart rate variability at low frequencies (usually from 0.04 to 0.15 Hz). The LF is influenced by sympathetic and parasympathetic activity and the child analyzase xunto coa IC. Expressed in milliseconds to frame (ms^2).	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
SD1 (standard deviation 1)	SD1 is xeometric measures derived from Poincaré graphs, which are graphical representations of RR intervals. SD1 represents the short-term variability perpendicular to the identity line in the Poincaré graphic and is influenced by parasympathetic activity.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
SD2 (standard deviation 2)	SD2 is a xeometric measure derived from Poincaré graphs, which are graphical representations of RR intervals. SD2 represents long-term variability along the identity line and is influenced by sympathetic and parasympathetic activity.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
DFAa1 (Trend Flotation Analysis, alpha-1)	DFA is a mathematical method used to evaluate fractal properties in time series, such as the HRV. DFAa1 centrase specifically in short-term floatation (alpha-1) in the HRV signal. It offers information about the properties of autosemellanza or long-range correlation of the signal.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
DFAa2 (Trend Flotation Analysis, alpha-2)	DFA is a mathematical method used to evaluate the fractal properties of time series, such as HRV. DFAa2 céntrase especially in long-term flotation (alpha-2) in the HRV signal.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
SampEn (Sample Entropy)	The show entropy is a modified algorithm less dependent on the duration of the time series. Used to evaluate the complexity of R-R intervals. A higher entropy value represents more complex dynamics and greater ability of the cardiovascular system to adapt to changes, which is associated with lower cardiovascular health.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
ApEn (approximate entropy)	ApEn is a measure used to evaluate the regularity and complexity of time series, such as HRV. ApEn quantifies the degree of unpredictability in the time series fluctuations, providing information about the structure of the signal and its irregularity. A lower value of ApEn indicates a more regular and predictable series, whereas a higher value reflects greater complexity and irregularity.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
MSE (Multiscale entropy)	MSE is an extension of SampEn that analyzes the complexity of time series on multiple time scales. The MSE allows to evaluate the structure of the signal at different levels of detail, providing a more complete view of its complexity.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
D2 (Correlation dimension)	The correlation dimension is a measure that estimates the minimum number of variables needed to build a model of the dynamics of a system. The greater the number of variables required to predict a time series, the greater its complexity. This measure provides information about the subcomplex and dynamic characteristics of the system.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Heart rate turbulence (HRT)	The cardiac frequency turbulence and a baroreflex-mediated axus of the cardiac frequency that acts as a countermechanism for premature ventricular contraction. It consists of no brief acceleration of the heart rate, followed by a slow decrease at the reference rate.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Heart rate (HR)	Number of heartbeats per minute during treatments performed during different trimesters of pregnancy and not postpartum (Lat/min).	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Systolic blood pressure (PAS)	Perform a systolic blood pressure record expressed in mmHg and measured in different locations.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Diastolic blood pressure (DBP)	Perform a diastolic blood pressure record expressed in mmHg and measured in different locations.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Mean arterial pressure (MAP)	MAP is the constant blood pressure value that, wedge same peripheral resistance would produce the same flow rate (minute cardiac volume) as xera a variable blood pressure (systolic and diastolic pressure) expressed in mmHg.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Pulse pressure (BP)	BP is an index of arterial distensibility expressed in mmHg obtained from the difference between systolic and diastolic blood pressure and measured in different locations.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
O2 saturation	Oxygen saturation measures, in different locations, the percentage of hemoglobin in red blood cells currently transporting oxygen, indicating how well the lungs and heart are oxygenating body tissues. The following are measured: Regional O2 saturation (StO2) using near-infrared spectroscopy (NIRS), Arterial O2 saturation (SpO2) uses standard pulse oximetry, Venous O2 saturation (SjvO2) requires invasive catheterization.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Cardiac output (CO)	Cardiac output is the total volume of blood pumped by the heart's left ventricle in one minute, serving as a critical indicator of cardiovascular health and tissue perfusion. It is measured in L/min multiplying the stroke volume (blood ejected per beat) by the heart rate (beats per minute) using an echocardiogram.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Stroke volume (SV)	Stroke volume is the volume of blood pumped from the left ventricle per beat. It is measured in mL using a volumetric formula whose values are obtained from cardiac imaging and hemodynamic monitoring techniques, such as echocardiography.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Systemic vascular resistance (SRV)	Systemic vascular resistance is measured by calculating the opposition to blood flow in the left ventricle using a formula. The essential values are mean arterial pressure (MAP), central venous pressure (CVP), and cardiac output (CO), usually obtained through invasive catheterization (Swan-Ganz catheter) or advanced hemodynamic monitoring methods. It is measured in dyn*s/cm^5	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Vasodilation / Constriction (VDCx)	Vasodilation (widening) and vasoconstriction (narrowing) of blood vessels (VDCx), which reflect vascular function and muscle tone, are measured in mm using non-invasive techniques that assess how an artery reacts to a stimulus. The standard method is Flow-Mediated Dilation (FMD) using ultrasound.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Cerebral vascular flow (CBF)	Cerebral blood flow is the net amount of blood delivered to the brain's capillary bed per unit of time and tissue mass, typically measured in mL/min/100g using various imaging and functional monitoring techniques, mainly classified into non-invasive methods (ultrasound, MRI) and perfusion techniques by tomography or nuclear medicine, intended to assess the amount and speed of blood reaching brain tissue.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Cardiac Index (CI)	The Cardiac Index is a hemodynamic parameter representing the heart's pumping efficiency, calculated as the cardiac output divided by the body surface area. It measures blood flow (liters per minute) relative to a person's size L/min/m^2 using Doppler Echocardiography.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Central Venous Pressure (CVP)	Central Venous Pressure is measured by connecting a central venous catheter to a manometer or electronic transducer, aligning the equipment with the phlebostatic point (level of the right atrium), and reading the fluid column (cm H2O) or the figure in mmHg that indicates the hydroelectrolytic balance and function of the right side of the heart, reflecting intravascular volume and cardiac preload.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Jugular venous distensibility (JVDx/JYI-DI)	Jugular venous distensibility is an index given by a formula whose data is obtained from ultrasound measurement to evaluate the response in the change of diameter of the veins to fluids and the volemia status.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
The Ankle-Brachial Index with Doppler (ABI-D or ITB)	The Ankle-Brachial Index with Doppler is a non-invasive diagnostic test used to evaluate peripheral arterial disease (PAD) by comparing systolic blood pressure at the ankle with that in the arm. It is measured by dividing the highest systolic pressure obtained at the ankle by the highest systolic pressure in the arms.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
The Cardio-Ankle Vascular Index (CAVI)	The Cardio-Ankle Vascular Index is measured non-invasively using a specialized device, commonly the VaSera (Fukuda Denshi, Japan), which automatically calculates stiffness from the origin of the aorta to the ankle. The procedure is based on pulse wave velocity (PWV) and blood pressure.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
The Acoustic Index Derived (AI-D)	The Acoustic Index Derived is a new metric in cardiology that is measured using AI-assisted automated echocardiography to assess cardiac function in real time. It is calculated by automatically analyzing ultrasound images to provide a comprehensive view of heart health.	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
PEP (Pre-Ejection Period)	The PEP (Pre-Ejection Period) in hemodynamics is a parameter measured in milliseconds (ms) that evaluates the time that elapses from the beginning of the electrical activation of the ventricle until the beginning of the ejection of blood towards the aorta. It is measured by calculating the time interval between the start of ventricular depolarization (Q wave of the ECG) and the beginning of aortic blood ejection (point B of impedance cardiography).	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Ejection Time (ET)	Ejection Time (ET) is the duration of systolic flow, measuring (in milliseconds) the time interval from aortic valve opening to closure when the left ventricle ejects blood into the aorta. Using Spectral Doppler (Pulsed or Continuous Wave) the time is measured from the start of the flow (valve opening) to the end of the aortic flow (valve closing).	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Age	Age expressed in years	Basal assessment
Race	Caucasian, Black or of African descent, Arab or North African, Asian, Native American, Latin American, Other	Basal assessment
Births	Nulliparous, primiparous, multiparous	Basal assessment
Fertilization	Spontaneous, Conventional IVF, ICSI, FET (frozen embryos), Mini IVF, Ovodonation, ROPA Method	Basal assessment
Risk of pre-eclampsia	High, Medium, Low	Basal assessment
Previous pregnancies	Number of pregnancies	Basal assessment
Previous spontaneous abortions	Number of pregnancies	Basal assessment
Type of childbirth	Spontaneuos vaginal, assisted vaginal, scheduled cesarean, urgent cesarean	Basal assessment
Time of childbirth	Pre-term, at term, post-term	Basal assessment
Level of education	No studies, primary education, secondary, baccalaureate, vocational training, university studies	Basal assessment
Employment status	Full-time paid employment, part-time paid employment, self employed, unemployed, dedication to the home	Basal assessment
Concomitant medication	Without medication, Analgesics, Antibiotics, Antivirals, Antifungals, Antiparasitics, Anti-inflammatory drugs, Antihistamines, Antihypertensive drugs, Hypoglycemic agents, Antidepressants, Anxiolytics, Antipsychotics, Diuretics, Anticoagulants, Nutritional supplementation, Antiemetics, Hormone treatment before pregnancy, Hormone treatment in pregnancy, Other	Basal assessment
Smoking habit	Non-smoker, Ex-smoker more than one year, Ex-smoker less than a year, Non-smoker during pregnancy, Smoker	Basal assessment
Consumption of alcohol	Non-consumer, Ex-consumer, Not consuming during pregnancy, Occasional consumer, Daily consumer	Basal assessment
Family history of disease	No background, High blood pressure, Type 2 diabetes mellitus (T2DM), Hypertensive disorders during pregnancy, Other	Basal assessment
Weight	Kg	Basal assessment
Height	Cm	Basal assessment
Pregnancy-associated plasma A protein (PAPP-A)	Biomarker of preeclampsia expressed in MoM	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Placental growth factor (PlGF)	Biomarker of preeclampsia expressed in pg/mL	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Ratio sFlt-1/PlGF	Biomarker of preeclampsia	Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Postpartum physical activity habits (IPAQ)	Low, moderate, high	Postpartum month, 3, 6 and 12 months.
Physical activity habits in pregnancy (PPAQ)	METS-h/week	Pregnancy weeks 13, 27 and 41
Postpartum specific anxiety scale (PSAS - ES)	Minimal anxiety, Mild anxiety, Moderate anxiety, Severe anxiety	Postpartum month, 3, 6 and 12 months.
Edinburgh Scale for Postnatal Depression (EPDS - ES)	No postnatal depression, Mild symptoms, Moderate symptoms, Significant symptoms	Postpartum month, 3, 6 and 12 months.
Maternal-fetal complications in pregnancy	No complications, Severe nausea and vomiting, Pre-eclampsia, Gestational hypertension, Gestational diabetes, Infections, Anemia, Detachment of placenta, Restriction of intrauterine growth, Placenta previa, Other	Pregnancy weeks 13, 27 and 41
Postpartum complications	No complications, Postpartum hypertension, Postpartum hemorrhage, Postpartum infections, Postpartum depression, Deep vein thrombosis or pulmonary embolism, Perineal pain, Other	Postpartum month, 3, 6 and 12 months.
Hospitalizations pregnancy	Number	Pregnancy weeks 13, 27 and 41
Reason hospitalization	No hospitalization, Severe nausea and vomiting, Infections, Abnormal vaginal bleeding, Postpartum bleeding, Postpartum infections, Complications from cesarean section, Mood disorders, Cardiorespiratory complications, Other	Pregnancy weeks 13, 27 and 41

Collaborators and Investigators

• Sponsor: Fundacin Biomedica Galicia Sur
• Investigators: Principal Investigator: Alicia González Represas, Instituto de Investigación Sanitaria Galicia Sur (IISGS)

Study record dates

Study Major Dates

• Study Start (Actual): May 19, 2025
• Primary Completion (Estimated): December 15, 2027
• Study Completion (Estimated): December 15, 2027

Study Registration Dates

• First Submitted: December 12, 2025
• First Submitted That Met QC Criteria: January 26, 2026
• First Posted (Actual): January 29, 2026

Study Record Updates

• Last Update Posted (Actual): February 17, 2026
• Last Update Submitted That Met QC Criteria: February 12, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Diagnostic Techniques and Procedures; Diagnosis; Circulatory and Respiratory Physiological Phenomena; Physical Examination; Vital Signs; Hemodynamics; Cardiovascular Physiological Phenomena; Blood Pressure
• Other Study ID Numbers: EMMA

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No