Long-term non-invasive ventilation in pregnancy

Key points

• Management of pregnant women on long-term non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) therapy poses a challenge in terms of worsening respiratory symptoms as a consequence of anatomical and physiological changes occurring in pregnancy.
• There is currently no evidence to guide the management of patients who require NIV/CPAP therapy from pre-conception to postpartum and there is limited evidence of the impact on the fetus.
• This study will determine the proportion of pregnant women presenting to obstetric services who are already established on NIV/CPAP and examine the management and perinatal outcomes of these women and their babies.

Surveillance period

1st April 2023 - 31st March 2025

Background

Non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) therapy (home 'assisted ventilation') is used to treat nocturnal hypoventilation observed in patients with chronic respiratory failure secondary to neuromuscular disease, obstructuve sleep apnoea (OSA) and chest wall deformity. Recent trends towards increasing maternal age and obesity in pregnancy in the UK increase the likelihood of sleep disordered breathing in the pregnant population. The most recent Royal College of Obstetricians and Gynaecologists guidelines (2018)⁽¹⁾ indicate that 21.3% of the antenatal population have a BMI that falls into the obese category. There are limited data reporting sleep disordered breathing in the pregnant population and it is predicted that from 15% to as high as 32% of pregnant women could have underlying OSA. Both OSA and obesity nocturnal hypoventilaion are associated with higher rates of hypertensive disease and diabetes mellitus and it would be reasonable to expect similar trends in pregnancy. It has also been suggested that basic physiological changes during pregnancy could increase incidence of OSA with nasal congestion and increase mucosal hyperaemia, risk of OSA and progression of symptoms, ideally in the pre-conception period². There is limited guidance on the management of pregnant women requiring non-invasive ventilation and little is known about the effect of non-invasive ventilation on the growing fetus (although it has been suggested that a fetus exposed to chronic states of hypoxia in pregnancy is at risk of growth restriction²).

This study will determine the proportion of pregnant women presenting to obstetric services who are already established on NIV/CPAP therapy and remain on NIV/CPAP therapy during pregnancy. The data provided will enable the delivery of a comprehensive multi-professional and multi-disciplinary management guide to improve outcomes.

Objective

To use the UK Obstetric Surveillance System (UKOSS) to describe the incidence of women requiring long-term NIV/CPAP therapy in pregnancy in the UK and examine the management and perinatal outcomes following this.

Research Questions

• How many pregnant women who present to obstetric servcices are already established on long-term non-invasive ventilation therapy?
• What is the true incidence of use of non-invasive ventilation in pregnancy in the UK per annum?
• What are the maternal, obstetric and perinatal outcomes in women requiring non-invasive ventilation in the UK?
• How are pregnant women requiring non-invasive ventilation (either at home or in hospital) in pregnancy assessed (including investigations, surveillance, setting changes in pregnancy)?

Case definition

Any pregnant woman who commenced non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) for a long-term condition, either prior to or during their current pregnancy, and who are booked for antenatal care in a UK obstetric unit.

Excluded: Women commencing NIV/CPAP for an acute condition such as Covid-19 infection.

Funding

This study is funded by a grant to Professor Hart at Guys and St Thomas' Hospitals NHS Foundation Trust.

Ethics committee approval

This study has been approved by the London - Brent REC (Ref. Number: 10/H0717/20).

Team investigators

Dr Surabhi Nanada, Dr Anita Banerjee, Dr Lindsay Arrandale, Dr Eui-Sik Suh and Prof Nicholas Hart, Guys and St Thomas' Hospital.

Lead investigators and principal contacts: Dr Surabhi Nanda and Dr Anita Banerjee.

Download a sample Data Collection Form (DCF)

UKOSS Non-invasive ventilation DCF

References

1. Denison FC et al. on behalf of the Royal College of Obsetricians and Gynaecologists (2018), Care of Women with Obesity in Pregnancy. Green-top Guideline No. 72. British Journal of Obstetrics and Gynaecology.

2. Dominguez JE, Krystal AD, Habib AS. Obstrutctive Sleep Apnea in Pregnant Women: a Review of Pregnany Outcomes and an Approach to Management. Anasth Analg 2018 Nov; 127(5):1167-1177.