Cystic Fibrosis in Pregnancy

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Key points

  • The number of recorded pregnancies in the UK of women with CF has increased over the last 5 years.
  • Pre-pregnancy lung function is often cited as the most important factor in predicting the outcomes of pregnancy for both mother and baby; however it is necessary to clarify the current outcomes in women with CF across the spectrum of lung function.
  • This study aims to provide reliable incidence and risk estimates and describe different management strategies across the UK, giving an accurate representation of current practice and outcomes.

Surveillance Period

1st March 2015 – 29th February 2017

Background

Advances in the care of people with CF have led to increasing survival, such that the median predicted survival age for patients in the UK with CF is now 41.4 years, and 53.1% of all females with the disease are over the age of sixteen[1]. Fertility in menstruating females with CF is near normal[2], and increasingly medical professionals are confronted with issues regarding fertility, family planning and pregnancy in this patient group.

Pre-pregnancy lung function is often cited as the most important factor in predicting the outcome of pregnancy for both mother and baby.  Maternal forced expiratory volume in one minute (FEV1) of less than 60% correlates with increased risk of premature delivery, delivery by caesarean section and adverse fetal outcomes such as low birth weight and perinatal death[3][4].  Based on the limited published evidence, a guideline was published in 2008 for the management of pregnant women with CF[5] which states that along with pre-existing pulmonary hypertension and cor pulmonale, an FEV1 of less than 50% predicted should be suggested as an absolute contraindication to pregnancy.  However, successful pregnancies have been documented in women with much greater impairment in lung function and pre-pregnancy FEV1 between 20% and 30% predicted are reported[3], leading to the suggestion that advising such women to avoid pregnancy may be unwarranted.  Further study is clearly necessary to clarify the current outcomes for pregnancy in women with CF across the spectrum of lung function.

It is hoped that the results obtained from this study will guide medical professionals in supporting the care of women both planning and during pregnancy and ultimately enabling them to make informed choices regarding pregnancy and planning a family.

Objective

To use the UK Obstetric Surveillance System (UKOSS) to determine the incidence and risk factors of CF in pregnancy and examine the management of the condition as well as maternal and neonatal outcomes. 

Research questions

  • What is the current UK incidence of women with CF in pregnancy?
  • What are the antenatal complications experienced?
  • What is the risk of a pre-term delivery?
  • How is delivery managed in pregnant women with CF?
  • What are the maternal and neonatal outcomes?
  • How does lung function prior to pregnancy correlate with these outcomes?

Case definition

All pregnant women with a diagnosis of CF confirmed by CF mutation genotyping either prior to or during the current pregnancy who are booked for antenatal care in a UK obstetric unit.

Funding

This study has been funded by Wellbeing of Women.

Ethics committee approval

This study has been approved by the North London REC1 (REC Ref. Number: 10/H0717/20).

Lead Investigator

Lucy Mackillop, Consultant in Obstetric Medicine, John Radcliffe Hospital, Oxford.

Download a Sample Data Collection Form (DCF)

UKOSS Cystic Fibrosis Form

References

  1. ^ UK CF Registry Annual Report Data 2010.
  2. ^ Edenborough FP.  Women with cystic fibrosis and their potential for reproduction.  Thorax. 2001 Aug; 56 (8): 649-55.
  3. a, b Thorpe-Beeston JG, Madge S, Gyi K, Hodson M, Bilton D.  The outcome of pregnancies in women with cystic fibrosis – single centre experience 1998-2011. BJOG 2012;119.
  4. ^ Edenborough FP, Mackenzie WE, Stableforth DE.  The outcome of 72 pregnancies in 55 women with cystic fibrosis in the United Kingdom 1977-1996.  BJOG 2000 Feb; 107(2):254-61.
  5. ^ Edenborough FP et al.  European Cystic Fibrosis Society.  Guidelines for the management of pregnancy in women with cystic fibrosis. J Cyst Fibros. 2008 Jan; 7 Suppl 1:S2-32.

Updated: Monday, 06 July 2020 18:39 (v18)