Pregnancy RelatedEMMANCT07376616
Cardiovascular Research in EMbarazo and MAternity (EMMA). Study on Heart Rate Variability and Hemodynamic Adaptations During Pregnancy and Postpartum.
An observational study of Pregnancy Related and Heart Rate Variation (HRV), run by Fundacin Biomedica Galicia Sur at 1 site in Spain.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older, women onlyHealthy volunteers can take part
- Conditions the study is for
- Pregnancy Related, Heart Rate Variation (HRV), Hemodynamics
- What is being tested?
- Assessment of HRV and blood pressure
- How many people
- 242 participants
- Where
- 1 siteSpain
- Study dates
- 19 May 2025to 15 Dec 2027
- How long will I take part?
- 21 Months
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Study population: Women pregnant from the first trimester of gestation over 18 years.
Who may be able to join
- Over 18 years of age
- Pregnancy from the third month of gestation
- No pre-existing cardiovascular disease
- Good cognitive level
- Sign informed consent
Who cannot join
- 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)
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- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site, 1 recruiting
- Recruiting
Hospital Alvaro Cunqueiro
Vigo, Pontevedra, 36312
Emilio Couceiro Naveira
Emilio.Couceiro.Naveira@sergas.es
About this study
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.
- Conditions
- Pregnancy Related, Heart Rate Variation (HRV), Hemodynamics
- Being tested
- Assessment of HRV and blood pressure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Assessment of HRV and blood pressureOther
Assessment of Heart Rate Variation (HRV) and blood pressure
| Study group | Role | What they receive |
|---|---|---|
| Unic group | Not described Receives: Other: Assessment of HRV and blood pressure |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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.
Measured: 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).
Measured: 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).
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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).
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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).
Measured: 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).
Measured: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Secondary outcomes (28)
Age
Age expressed in years
Measured: Basal assessment
Race
Caucasian, Black or of African descent, Arab or North African, Asian, Native American, Latin American, Other
Measured: Basal assessment
Births
Nulliparous, primiparous, multiparous
Measured: Basal assessment
Fertilization
Spontaneous, Conventional IVF, ICSI, FET (frozen embryos), Mini IVF, Ovodonation, ROPA Method
Measured: Basal assessment
Risk of pre-eclampsia
High, Medium, Low
Measured: Basal assessment
Previous pregnancies
Number of pregnancies
Measured: Basal assessment
Previous spontaneous abortions
Number of pregnancies
Measured: Basal assessment
Type of childbirth
Spontaneuos vaginal, assisted vaginal, scheduled cesarean, urgent cesarean
Measured: Basal assessment
Time of childbirth
Pre-term, at term, post-term
Measured: Basal assessment
Level of education
No studies, primary education, secondary, baccalaureate, vocational training, university studies
Measured: Basal assessment
Employment status
Full-time paid employment, part-time paid employment, self employed, unemployed, dedication to the home
Measured: 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
Measured: Basal assessment
Smoking habit
Non-smoker, Ex-smoker more than one year, Ex-smoker less than a year, Non-smoker during pregnancy, Smoker
Measured: Basal assessment
Consumption of alcohol
Non-consumer, Ex-consumer, Not consuming during pregnancy, Occasional consumer, Daily consumer
Measured: Basal assessment
Family history of disease
No background, High blood pressure, Type 2 diabetes mellitus (T2DM), Hypertensive disorders during pregnancy, Other
Measured: Basal assessment
Weight
Kg
Measured: Basal assessment
Height
Cm
Measured: Basal assessment
Pregnancy-associated plasma A protein (PAPP-A)
Biomarker of preeclampsia expressed in MoM
Measured: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Placental growth factor (PlGF)
Biomarker of preeclampsia expressed in pg/mL
Measured: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Ratio sFlt-1/PlGF
Biomarker of preeclampsia
Measured: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Postpartum physical activity habits (IPAQ)
Low, moderate, high
Measured: Postpartum month, 3, 6 and 12 months.
Physical activity habits in pregnancy (PPAQ)
METS-h/week
Measured: Pregnancy weeks 13, 27 and 41
Postpartum specific anxiety scale (PSAS - ES)
Minimal anxiety, Mild anxiety, Moderate anxiety, Severe anxiety
Measured: Postpartum month, 3, 6 and 12 months.
Edinburgh Scale for Postnatal Depression (EPDS - ES)
No postnatal depression, Mild symptoms, Moderate symptoms, Significant symptoms
Measured: 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
Measured: 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
Measured: Postpartum month, 3, 6 and 12 months.
Hospitalizations pregnancy
Number
Measured: 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
Measured: Pregnancy weeks 13, 27 and 41
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jan 2026
- Study start19 May 2025
- Primary completion15 Dec 2027 (estimated)
- Study completion15 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pregnancy RelatedStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 242 participants (estimated)
- Target duration
- 21 Months
Sponsor and investigators
- Lead sponsor
- Fundacin Biomedica Galicia Sur
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Alicia González Represas, Principal investigator, Instituto de Investigación Sanitaria Galicia Sur (IISGS)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07376616
- Sponsor's protocol ID
- EMMA
- Acronym
- EMMA
- Status last verified
- Feb 2026
- First submitted
- 12 Dec 2025
- Last updated
- 17 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cardiovascular Research in EMbarazo and MAternity (EMMA). Study on Heart Rate Variability and Hemodynamic Adaptations During Pregnancy and Postpartum.
- ClinicalTrials.gov ID
- NCT07376616
- Acronym / sponsor ID
- EMMA / EMMA
- Conditions
- Pregnancy Related, Heart Rate Variation (HRV), Hemodynamics
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 242 participants (estimated)
- Lead sponsor
- Fundacin Biomedica Galicia SurUniversity, hospital or other
- Study start
- 19 May 2025 (actual)
- Primary completion
- 15 Dec 2027 (estimated)
- Study completion
- 15 Dec 2027 (estimated)
- First posted
- 29 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Observational model
- Case only
- Time perspective
- Prospective
- Target follow-up
- 21 Months
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Unic group | – | Other: Assessment of HRV and blood pressure |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Women pregnant from the first trimester of gestation over 18 years.
Key inclusion criteria (5 listed)
- Over 18 years of age
- Pregnancy from the third month of gestation
- No pre-existing cardiovascular disease
- Good cognitive level
- Sign informed consent
Key exclusion criteria (22 listed)
- Diabetes mellitus
- Hyperthyroidism
- Hypothyroidism
- Chronic hypertension diagnosed before pregnancy
- Heart failure
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Assessment of HRV and blood pressureAssessment of Heart Rate Variation (HRV) and blood pressure | Other | Unic group |
Primary outcome
RR (R-R range)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
RMSSD (Root Mean Square of Successive Differences)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
pNN50 (Percentage of successive RR intervals differing by more than 50 ms)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
HF (High Frecuency)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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).
LF (low frequency)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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).
SD1 (standard deviation 1)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
SD2 (standard deviation 2)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
DFAa1 (Trend Flotation Analysis, alpha-1)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
DFAa2 (Trend Flotation Analysis, alpha-2)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
SampEn (Sample Entropy)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
ApEn (approximate entropy)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
MSE (Multiscale entropy)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
D2 (Correlation dimension)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Heart rate turbulence (HRT)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Heart rate (HR)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Number of heartbeats per minute during treatments performed during different trimesters of pregnancy and not postpartum (Lat/min).
Systolic blood pressure (PAS)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Perform a systolic blood pressure record expressed in mmHg and measured in different locations.
Diastolic blood pressure (DBP)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Perform a diastolic blood pressure record expressed in mmHg and measured in different locations.
Mean arterial pressure (MAP)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Pulse pressure (BP)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
O2 saturation
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Cardiac output (CO)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Stroke volume (SV)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Systemic vascular resistance (SRV)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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
Vasodilation / Constriction (VDCx)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Cerebral vascular flow (CBF)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Cardiac Index (CI)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Central Venous Pressure (CVP)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
Jugular venous distensibility (JVDx/JYI-DI)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
The Ankle-Brachial Index with Doppler (ABI-D or ITB)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
The Cardio-Ankle Vascular Index (CAVI)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
The Acoustic Index Derived (AI-D)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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.
PEP (Pre-Ejection Period)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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).
Ejection Time (ET)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
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).
28 secondary outcomes
Age
Time frame: Basal assessment
Race
Time frame: Basal assessment
Births
Time frame: Basal assessment
Fertilization
Time frame: Basal assessment
Risk of pre-eclampsia
Time frame: Basal assessment
Previous pregnancies
Time frame: Basal assessment
Previous spontaneous abortions
Time frame: Basal assessment
Type of childbirth
Time frame: Basal assessment
Time of childbirth
Time frame: Basal assessment
Level of education
Time frame: Basal assessment
Employment status
Time frame: Basal assessment
Concomitant medication
Time frame: Basal assessment
Smoking habit
Time frame: Basal assessment
Consumption of alcohol
Time frame: Basal assessment
Family history of disease
Time frame: Basal assessment
Weight
Time frame: Basal assessment
Height
Time frame: Basal assessment
Pregnancy-associated plasma A protein (PAPP-A)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Placental growth factor (PlGF)
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Ratio sFlt-1/PlGF
Time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.
Postpartum physical activity habits (IPAQ)
Time frame: Postpartum month, 3, 6 and 12 months.
Physical activity habits in pregnancy (PPAQ)
Time frame: Pregnancy weeks 13, 27 and 41
Postpartum specific anxiety scale (PSAS - ES)
Time frame: Postpartum month, 3, 6 and 12 months.
Edinburgh Scale for Postnatal Depression (EPDS - ES)
Time frame: Postpartum month, 3, 6 and 12 months.
Maternal-fetal complications in pregnancy
Time frame: Pregnancy weeks 13, 27 and 41
Postpartum complications
Time frame: Postpartum month, 3, 6 and 12 months.
Hospitalizations pregnancy
Time frame: Pregnancy weeks 13, 27 and 41
Reason hospitalization
Time frame: Pregnancy weeks 13, 27 and 41
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Alicia González Represas principal investigator
Instituto de Investigación Sanitaria Galicia Sur (IISGS)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Pregnancy Related and Heart Rate Variation (HRV), run by Fundacin Biomedica Galicia Sur at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 22 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Alicia González Represas (616044977, alicia@uvigo.gal), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
RR (R-R range) (time frame: Pregnancy weeks 13, 27 and 41. Postpartum month, 3, 6 and 12 months.). The study lists 33 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Feb 2026.