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Fontan and Pregnancy

Key points

  • The Fontan repair is performed as a palliative procedure to improve survival in infants born with a functionally univentricular circulation.
  • Pregnancy in women with a Fontan repair is rare and data regarding management of these women is sparse.
  • The results of this study will help optimise the future management of pregnant women with a Fontan circulation to obtain the best outcomes for mother and baby.

Surveillance Period

1st January 2019 – 31st May 2022


The Fontan repair describes a palliative surgical procedure that is undertaken for patients born with congenital heart defect that cannot support a biventricular circulation. Congenital heart disease is the most common congenital abnormality, affecting one in one hundred babies, and the number of adults who have undergone a Fontan repair is increasing[1]. Historically women were advised against pregnancy because it was felt to be too high risk, but in the last 10 years we have more retrospective data to show that these women are able to carry a pregnancy, albeit with a relatively high rate of complications[1][2][3].

Women with a Fontan circulation are known to have a higher rate of miscarriage (some studies report rates of almost 70%[1]) and a higher rate of postpartum haemorrhage than any other congenital heart disease group[4]. There is no consensus on whether women with a Fontan circulation should routinely be offered anticoagulation during pregnancy (either at prophylactic or therapeutic dosing levels). It is also unknown whether pregnancy accelerates the progressive deterioration of the function of a Fontan circulation.

The aims of this study are to prospectively collect data on a cohort of women embarking upon pregnancy with a Fontan repair to describe current pregnancy management and outcomes and to evaluate if pregnancy has a detrimental impact upon cardiac function in the short term.


To use the UK Obstetric Surveillance System (UKOSS) to determine the incidence of pregnancy amongst women with prior Fontan repair in the UK and examine the management and perinatal outcomes of such pregnancies.

Research questions

  • What is the rate of miscarriage in women with a Fontan repair and are there any maternal factors which influence this?
  • How should women with a Fontan repair be managed with regard to anticoagulation during pregnancy and are certain anticoagulation strategies associated with better or worse pregnancy outcomes?
  • Is there clear correlation between baseline oxygen saturation, ventricular function and pregnancy outcome?
  • What are the perinatal outcomes in women with a Fontan repair?
  • Are rates of preterm labour in this group of women largely iatrogenic or due to spontaneous preterm birth?
  • Does pregnancy have a detrimental effect upon short term cardiac function?

Case definition

All women with prior Fontan repair who have a pregnancy, regardless of outcome.


This study is being funded by Borne.

Ethics committee approval

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

Lead Investigator

Matthew Cauldwell and Mark Johnson, Chelsea and Westminster; Michael Gatzoulis, Royal Brompton; Philip Steer, Imperial College; Marian Knight, NPEU.

Sample Data Collection Form

UKOSS Fontan Data Collection Form


  1. a, b, c Cauldwell M, Steer PJ, Bonner S, Asghar O, Swan L, Hodson K, Head CEG et al. Retrospective UK multicentre study of the pregnancy outcomes of women with a Fontan repair. Heart. 2018 Mar;104(5):401-406.
  2. ^ Canobbio MM, Mair DD, vand der Velde M, Koos BJ. Pregnancy outcomes after the Fontan repair. J Am Coll Cardiol. 1996 Sep;28(3):763-7.
  3. ^ Gouton M, Nizard J, Patel M, Sassolas F, Jimenez M et al. Maternal and fetal outcomes of pregnancy with Fontan circulation: A multicentric observational study. Int J Cardiol. 2015;187:84-9.
  4. ^ Cauldwell M, Von Klemperer K, Uebing A, Swan L, Steer PJ, Gatzoulis M, Johnson MR. Why is post-partum haemorrhage more common in women with congenital heart disease? Int J Cardiol. 2016 Sep 1;218:285-290.

Updated: Tuesday, 17 January 2023 17:47 (v11)