Does Prone Position Alter Maternal Cardiorespiratory Status?

Does Maternal Prone Position Affect Maternal Cardiorespiratory Status or the Fetal Heart Rate?

During pregnancy women may need or choose to undergo physical therapies such as physiotherapy, massage or osteopathy. Recent findings from studies of mothers who had a stillbirth in late pregnancy found that the position in which women went to sleep in was linked to stillbirth, as was the frequency of day time naps. This link is thought to be due to changes in mother's blood flow from her heart when lying flat leading to changes in the amount of oxygen going to her baby. This raise concerns that spending extended periods laid flat could be detrimental to baby's health. However, it is not known whether lying flat for extended periods for physical therapies could also alter a baby's heart rate or levels of oxygen. One small study of 33 women from Brazil found that there were no differences in a mother's heart rate, blood pressure, oxygen saturation or baby's heart rate. But there were changes in mother's breathing rate and systolic blood pressure when a mother laid on her front. All the women reported feeling comfortable lying flat (on a bent surface). However, in this study women only spent 6 minutes in each position which is less than a woman would be expected to spend lying in a position for a session of physical therapy. The investigators plan a study to assess whether using a device to support a prone position (Anna cushion) would be associated with changes in mother's heart rate, blood pressure, breathing rate and blood oxygen levels and baby's heart rate. The investigators will also ask about mother's levels of comfort while she is laid in the prone position. The findings of this study will give an indication whether supporting a mother to lie in a prone position for physical therapies is safe and comfortable.

Study Overview

• Status: Completed
• Conditions: Pregnancy-Related Condition, Unspecified
• Intervention / Treatment: Other: Maternal prone position

Detailed Description

Women frequently experience lower-back or pelvic pain during pregnancy. This may lead to a need for physical therapies such as physiotherapy, osteopathy or massage in late pregnancy. Several case-control studies, and a recent individual patient data meta-analysis has demonstrated an association between going to sleep position and late stillbirth (a greater than 2-fold increased risk with going to sleep supine) and increased frequency of daytime naps. This is thought to be related to maternal haemodynamic changes when a mother lies supine in late pregnancy which decreases cardiac output and uterine blood flow. These changes are accompanied by alterations in fetal behaviour which are consistent with a reduction in oxygenation. This observation raises concerns that spending extended periods laid flat could be detrimental to baby's health. However, it is not known whether lying flat for extended periods for physical therapies could also alter a baby's heart rate or levels of oxygen. One small study of 33 women from Brazil which randomised the order of maternal positions found that there were no differences in a mother's heart rate, blood pressure, oxygen saturation or baby's heart rate between a supine, lateral and prone position (bent over a concave couch). However, there were observed changes in mother's breathing rate and systolic blood pressure when a mother laid on her front. Nevertheless, all the women reported feeling comfortable lying flat (on a bent surface). However, in this study women only spent 6 minutes in each position which is less than a woman would be expected to spend lying in a position for a session of physical therapy. Therefore, further work is required to determine whether spending extended periods laid prone is safe for mother and baby.

The co-investigator (Karli Büchling) has developed a cushion to support mothers in a prone position (Anna cushion). This study will investigate whether adopting this position supported by the cushion is associated with changes in mother's heart rate, blood pressure, breathing rate and blood oxygen levels and fetal heart rate as assessed by the cardiotocograph. The investigators will also ask about mother's levels of comfort while she is laid flat. The findings of this study will give an indication whether supporting a mother to lie in a prone position for physical therapies is safe and comfortable.

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Manchester, United Kingdom, M13 9WL
    • Manchester University NHS Foundation Trust

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• Viable singleton pregnancy ≥28 weeks' gestation
• No fetal anomalies according to Fetal Anomaly Screening Programme definition
• Ability to give written informed consent
• Maternal Age >16 years

Exclusion Criteria:

• Unable to read English (as the survey instruments are only available in English)
• Multiple pregnancy
• Pre-existing maternal cardiovascular or respiratory disease
• Fetal anomaly
• Contraindication to lying prone (severe pain etc.)
• Allergy to self-adhesive electrodes used for standard electrocardiography (ECG)
• Unable to give written informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Maternal Prone Position; Participants will initially be assessed in left-lateral position for 20 minutes. Participants will then be asked to lie in a prone position for 30 minutes supported by a specially designed pillow. Participants will then return to a left-lateral position for 20 minutes.	Other: Maternal prone position; Women will be asked to lie in a prone position supported by a specially designed cushion for 30 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maternal cardiac output at Baseline	Maternal cardiac output as assessed by non-invasive cardiac monitoring.	At baseline
Change in maternal cardiac output	Maternal cardiac output as assessed by non-invasive cardiac monitoring in prone position. Change calculated as Maternal cardiac output after 30 minutes in prone position - baseline cardiac output.	After 30 minutes in prone position

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maternal heart rate at baseline	Maternal heart rate as assessed by non-invasive monitoring (as beats per minute).	At baseline
Change in maternal heart rate	Maternal heart rate as assessed by non-invasive monitoring (as beats per minute) in prone position. Change calculated as Maternal heart rate after 30 minutes in prone position - baseline heart rate.	After 30 minutes in prone position
Maternal respiratory rate	Maternal respiratory rate as assessed by counting respirations (per minute)	At baseline
Change in maternal respiratory rate	Maternal respiratory rate as assessed by counting respirations (per minute) in prone position. Change calculated as Maternal respiratory rate after 30 minutes in prone position - baseline respiratory rate.	After 30 minutes in prone position
Maternal blood pressure	Both maternal systolic and diastolic blood pressure as assessed noninvasive blood pressure monitoring	At baseline
Change in maternal blood pressure	Both maternal systolic and diastolic blood pressure as assessed noninvasive blood pressure monitoring in prone position. Change calculated as maternal systolic blood pressure after 30 minutes in prone position - baseline systolic blood pressure or maternal diastolic blood pressure after 30 minutes in prone position - baseline diastolic blood pressure.	After 30 minutes in prone position
Oxygen saturation	Oxygen saturation measured by pulse oximetry	At baseline
Change in oxygen saturation	Oxygen saturation measured by pulse oximetry in prone position. Change calculated as Maternal oxygen saturation after 30 minutes in prone position - baseline oxygen saturation.	After 30 minutes in prone position
Fetal heart rate	Fetal wellbeing assessed by continuous cardiotocography which will report baseline heart rate, variability, the presence of accelerations or decelerations.	Baseline
Change in fetal heart rate	Fetal wellbeing assessed by continuous cardiotocography which will report baseline heart rate, variability, the presence of accelerations or decelerations.	Afer 30 minutes in prone position

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maternal Anxiety	Maternal anxiety will be assessed using the State Trait Anxiety Index (scores range from 20-80, where higher scores indicate greater anxiety).	Before the experimental protocol
Maternal Anxiety	Maternal anxiety will be assessed using the State Trait Anxiety Index (scores range from 20-80, where higher scores indicate greater anxiety).	Immediately after the completion of the experimental protocol
Maternal comfort as assessed by visual analogue scale	Maternal comfort as assesed by a visual analogue scale from 0-10. Higher scores indicate greater discomfort.	Before the experimental protocol
Maternal comfort as assessed by visual analogue scale	Maternal comfort as assesed by a visual analogue scale from 0-10. Higher scores indicate greater discomfort.	Immediately after the completion of the experimental protocol
Maternal comfort as assessed by self-reported questionnaire	Maternal comfort as assessed by self-reported questionnaire using Likert scales (from 1-5, where higher scores indicate greater agreement with the statement) and free-text responses	Immediately after the completion of the experimental protocol

Collaborators and Investigators

• Sponsor: University of Manchester

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2021
• Primary Completion (Actual): March 31, 2022
• Study Completion (Actual): May 16, 2022

Study Registration Dates

• First Submitted: September 22, 2020
• First Submitted That Met QC Criteria: October 13, 2020
• First Posted (Actual): October 14, 2020

Study Record Updates

• Last Update Posted (Actual): May 18, 2022
• Last Update Submitted That Met QC Criteria: May 16, 2022
• Last Verified: May 1, 2022

More Information

Terms related to this study

• Keywords: Cardiac output; Cardiotocography; Maternal anxiety; Fetal heart rate; Maternal prone position
• Additional Relevant MeSH Terms: Pregnancy Complications
• Other Study ID Numbers: IRAS240071

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: There is currently no plans to make individual participant data available to other researchers.

Drug and device information, study documents

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