Fontan Circulation and Reproductive Health in a National Swedish Cohort

Every year, approximately 2000 children are born with congenital heart defects in Sweden. In a small percentage of these cases, the heart defects are so severe that they cannot be corrected to resemble or function like a healthy heart. Instead, these highly complex heart defects are operated on to establish "single-ventricle circulation," also known as Fontan circulation or TCPC circulation (total cavopulmonary connection). This means there is only one chamber in circulation, pumping blood into the body's main artery. To facilitate venous blood flow to the lungs for oxygenation and back to the heart chamber, high venous pressure and low resistance in the lung circulation are required.

This type of blood circulation can lead to severe complications later in life, including heart failure, low oxygen saturation, blood clot formation, liver cirrhosis, bleeding, protein-losing enteropathy, arrhythmias, and reduced physical capacity. In the Swedish registry for congenital heart defects, SWEDCON, over 230 patients with single-ventricle circulation are registered in the adult section.

Congenital heart defects affect career choices, family planning, and leisure activities. Questions regarding heredity and pregnancy are common. The severity of different heart defects varies and has varying degrees of impact on patients' daily lives. Pregnancy and childbirth exert significant stress on a woman and her body. Due to the increased metabolic needs of the fetus and the mother, hemodynamics change during a normal pregnancy, with approximately a 40-50% increase in cardiac output and plasma volume. Pregnancy is often well tolerated by women with congenital heart defects, but there might be an increased risk of complications associated with pregnancy and childbirth. Women with complex congenital heart defects have a higher risk of experiencing cardiovascular events during pregnancy compared to women with simpler congenital heart defects. There is also a greater risk of infertility for these women. The modified WHO classifications system (mWHO class I-IV) can be used to assess risk associated with pregnancy and childbirth for women with heart disease, where higher class is associated with increased morbidity and mortality. In Fontan circulation, the risk of complications during pregnancy is considered high if the woman is classified as mWHO III or IV. If a woman experiences complications due to Fontan circulation before pregnancy, she is classified as mWHO IV and will be discouraged from pregnancy due to a very high risk for both maternal and fetal complications. During pregnancy, there is an increased risk of arrhythmias, heart failure symptoms, and thrombosis. Miscarriage risk is high for women with Fontan circulation, and preterm delivery is common, often resulting in low birth weight for gestational age. There is also an increased risk of peripartum bleeding. It is recommended that patients with Fontan circulation have frequent check-ups during pregnancy and in the first weeks after delivery.

Some women with complex congenital heart defects choose not to undergo pregnancy due to their heart condition. Others choose to become pregnant despite being informed about the high risks and advice against pregnancy, which places high demands on the care and follow-up of these patients. How men with Fontan circulation perceive their parental abilities and the possibility of having children is poorly studied, as well as how a partner of a person with complex congenital heart defects thinks and reasons about parenthood.

The impact of Fontan circulation on reproductive health and fertility needs to be illuminated, and additional studies are required from both medical and psychosocial perspectives.