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NCT Number: NCT04476368

Effect of Yoga in Pregnancy on Cardio-respiratory Adaptation to Challenge

Yoga has received considerable attention for its potential therapeutic benefits over the past decades and it gradually became object of scientific scrutiny. There is currently extensive literature supporting its use as a non-pharmacological tool for managing a variety of medical problems. A few studies have also explored potential beneficial effects of practising yoga during pregnancy on maternal and neonatal outcomes. An association between prenatal yoga and decreased incidence of fetal growth restriction, preterm delivery, and labor abnormalities resulting in operative delivery have been reported.

Exact mechanisms by which yoga could improve perinatal outcomes have not been elucidated yet. One of such mechanisms could be the positive effect of yoga on autonomic nervous system (ANS). Maternal cardiovascular system undergoes profound changes during pregnancy and ANS plays a central role in adaptation to pregnancy-related hemodynamic changes. Increase in peripheral vascular resistance that characterises hypertensive disorders in pregnancy with fetal growth restriction is mediated by substantial increase in sympathetic vasoconstrictor activity. Effects of yoga on ANS outside of pregnancy have already been investigated in several studies. Heart rate variability (HRV) indices, used as a one of proxy measures for ANS activity, showed significant shifts towards parasympathetic dominance following yoga sessions. Another objective means of assessing ANS activity is measurement of phase synchronisation between cardiovascular and respiratory systems following acute challenge. The higher the cardiorespiratory synchronisation after acute challenge is, the higher is the ability of ANS to flexibly adapt to challenge.

The objectives of the study are:

I. To examine whether there is a short-term shift in autonomic balance to the parasympathetic branch of the ANS and ability of the cardiovascular and respiratory respiratory systems to flexibly adapt to acute psychological challenge following sessions in pregnancy.

II. To investigate potential long- term effects of yoga practice during pregnancy on HRV and cardio-respiratory synchronisation following acute psychological challenge.

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Key information

Conditions

Yoga Autonomic Nervous System Pregnancy

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

UMC Ljubljana, Ljubljana, Slovenia

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy pregnant women with singleton pregnancies.

Exclusion criteria

  • Multiple pregnancies
  • Cardiovascular disease (including hypertension and arrhythmias)
  • Taking medications that would affect heart rate or blood pressure
  • Psychiatric disorders
  • Epilepsy
  • Kidney disease
  • Liver disease
  • Known fetal anomaly
  • Autoimmune disorders
  • Thyroid disease
  • Diabetes mellitus
  • Alcohol/drug abuse

Treatment and study plan

weekly yoga classes

Other

Weekly 90 min pregnancy-adapted yoga classes lead by certified yoga instructors.

Walk

Other

20-30 min easy walking

Primary outcomes

  1. Change in cardio-respiratory phase synchronisation index

    Time frame: Change in cardio-respiratory phase synchronisation index from baseline (measured up to 30 minutes before yoga class/walk) to the end of exercise (measured up to 30 minutes after the end of yoga class/walk)

    Cardio-respiratory phase synchronisation index measures synchronisation between the cardiovascular and respiratory system following acute psychological challenge. It's value is between 0 (no synchronisation) and 1 (complete synchronisation). The higher the value, the higher the ability of cardiovascular and respiratory systems to flexibly adapt to challenge (standardised memory task).

  2. Change in LF/HF HRV ratio.

    Time frame: Change in LF/HF HRV ratio from baseline (measured up to 30 minutes before yoga class/walk) to the end of exercise (measured up to 30 minutes after the end of yoga class/walk).

    For frequency related HRV indices, we will run an autoregressive spectral analysis using Burg's algorithm (model order 24) after resampling and removing the trend of 2nd order. Low frequency (LF) will be defined as 0.04 - 0.15 Hz, high frequency (HF) will be defined as 0.15 - 0.40 Hz. The higher the LF/HF HRV ratio, the lower the parasympathetic tone.

  3. BRS

    Time frame: Change in BRS from baseline (measured up to 30 minutes before yoga class/walk) to the end of exercise (measured up to 30 minutes after the end of yoga class/walk).

    The sequence technique will be used for the assessment of baroreceptor sensitivity (BRS). This technique is based on identifying consecutive cardiac beats in which an increase in systolic blood pressure is accompanied by an increase in heart rate, or in which a decrease in systolic blood pressure is accompanied by a decrease in heart rate. The regression line between the systolic blood pressure and heart rate produces an estimate of BRS. The higher the BRS, the higher the parasympathetic tone.

Sponsors and collaborators

Lead sponsor

University Medical Centre Ljubljana

Other

Collaborators

  • University Medical Centre Maribor

Registry information

Official study title

Effect of Yoga in Pregnancy on Cardiovascular and Respiratory Adaptation to Acute Psychological Challenge

Acronym: YOGADAPT

Important dates

Study start
2020
Primary completion
2022
Study completion
2022
First posted
Jul 20, 2020
Registry last updated
Jun 27, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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