Pregnancy outcomes in patients with a fontan circulation and proposal for a risk-scoring system: single centre experience

Pregnancy Outcomes in Women after the Fontan Procedure

Women with single ventricle physiology after the Fontan procedure, despite numerous possible complications, can reach adulthood and give birth. Pregnancy poses a hemodynamic burden for distorted physiology of Fontan circulation, but according to the literature, it is usually well tolerated unless the patient is a "failing" Fontan. Our study aimed to assess maternal and fetal outcomes in patients after the Fontan procedure followed up in two tertiary Polish medical centers. We retrospectively evaluated all pregnancies in women after the Fontan procedure who were followed up between 1995-2022. During the study period, 15 women after the Fontan procedure had 26 pregnancies. Among 26 pregnancies, eleven ended with miscarriages, and 15 pregnancies resulted in 16 live births. Fetal complications were observed in 9 (56.3%) live births, with prematurity being the most common complication (n = 7, 43.8%). We recorded 3 (18.8%) neonatal deaths. Obstetrical complications were present in 6 (40%) out of 15 completed pregnancies-two (13.3%) cases of abruptio placentae, two (13.3%) pregnancies with premature rupture of membranes, and two (13.3%) patients with antepartum hemorrhage. There was neither maternal death nor heart failure decompensation during pregnancy. In two (13.3%) women, atrial arrhythmia developed. One (6.7%) patient in the second trimester developed ventricular arrhythmia. None of the patients suffered from systemic thromboembolism during pregnancy. Pregnancy in women after the Fontan procedure is well tolerated. However, it is burdened by a high risk of miscarriage and multiple obstetrical complications. These women require specialized care provided by both experienced cardiologists and obstetricians.

Reproductive Issues in Patients With the Fontan Operation

Patients with the Fontan operation have a unique circulation, with a limited ability to increase cardiac output, and high central venous pressure. They may have diastolic and/or systolic ventricular dysfunction, arrhythmias, thromboembolic complications, or multiorgan dysfunction. All of these factors contribute to reproductive issues, including menstrual irregularities, infertility, recurrent miscarriage, and complications during pregnancy. Although atrial arrhythmias are the most common cardiac complications during pregnancy, patients can develop heart failure and thromboembolic events. Obstetric bleeding, including postpartum hemorrhage, is common. In addition to maternal complications, adverse fetal and neonatal events, such as prematurity and low birthweight, are very common. Counselling about these reproductive issues should begin early. For those who become pregnant, care should be provided by a multidisciplinary cardio-obstetric team familiar with the specific issues and needs of the Fontan population. In this review, we discuss infertility, contraception, and pregnancy in patients with the Fontan operation.

Pregnancy in the FONTAN palliation: physiology, management and new insights from bioengineering

Fontan palliation for the single ventricle results in a challenging and delicate physiological state. At rest, the body adapts to a low cardiac output and high systemic venous pressure. However, when physiological demands increase, such as in the case of exercise or pregnancy, this delicate physiology struggles to adapt due to the inability of the heart to pump blood into the lungs and the consequent lack of augmentation of the cardiac output.

Due to the advances in paediatric cardiology, surgery and intensive care, today most patients born with congenital heart disease reach adulthood. Consequently, many women with a Fontan circulation are becoming pregnant and so far data suggest that, although maternal risk is not high, the outcomes are poor for the foetus. Little is known about the reasons for this disparity and how the Fontan circulation adapts to the physiological demands of pregnancy.

Here we review current knowledge about pregnancy in Fontan patients and explore the potential role of computational modelling as a means of better understanding this complex physiology in order to potentially improve outcomes, particularly for the foetus.

Maternal Fontan procedure is a predictor of a small-for-gestational-age neonate: a 10-year retrospective study

BACKGROUND

Women with single ventricle cardiac physiologic condition who have undergone Fontan procedures are surviving well into reproductive age and historically have been discouraged from pregnancy, despite the paucity of data regarding maternal and neonatal outcomes.

OBJECTIVE

Our primary objective was to investigate, in a large cohort, the maternal and neonatal outcomes of pregnant women who have undergone the Fontan procedure and to understand maternal and neonatal sequelae of their pregnancies.

STUDY DESIGN

This single-center retrospective cohort study involves pregnant women with a Fontan palliation who delivered at UCLA Medical Center over a 10-year period (2007-2017). All pregnancies were evaluated for differences in maternal and neonatal characteristics.

RESULTS

We identified 37 distinct pregnancies in 24 women with a Fontan procedure. The physiologic pregnancy-related increase in cardiac output is blunted substantially in Fontan circulation. Third-trimester cardiac index positively correlated to birthweight z-score (R²=0.48; P=.038) but not to small for gestational age (R²=0.13; P=.339). The most common cardiac complications in pregnancies of >24 weeks gestation were sustained arrhythmia (37.5%) and decompensated heart failure (21%). The 37 pregnancies comprised 25 live births (67.6%), 1 fetal death (2.7%), 9 spontaneous abortions (24%), and 2 pregnancy terminations (5.4%). Of the live births, 60% were preterm at an average gestational age of 34.9±3.7 weeks. Newborn infants were delivered via cesarean in 53%, operative vaginal delivery in 28%, and spontaneous vaginal delivery in 20%. Forty percent of neonates were born small (<10th percentile) for gestational age; 44.0% of all neonates were admitted to the neonatal intensive care unit.

CONCLUSION

Women with a single ventricle and Fontan circulation can have a successful pregnancy, although they are at increased risk for arrhythmias and heart failure. The decreased cardiac reserve in these pregnancies blunts the normal increase in maternal cardiac output, which is associated with preterm delivery and small-for-gestational-age neonates. Further studies are needed to determine to what extent the impaired rise in maternal cardiac output reduces uteroplacental perfusion, placental exchange, fetal growth, and onset of parturition.

Success in a Fontan pregnancy: how important is ventricular function?

The Fontan operation is a palliative surgical procedure for patients whose hearts cannot support a biventricular circulation. The haemodynamic changes that occur in pregnancy are particularly challenging for Fontan patients and the outcomes are variable. We present a case where fetal outcome was particularly poor despite a lack of high risk features pre-pregnancy.