Twin reversed arterial perfusion sequence (TRAP sequence), also known as acardiac twinning, is a rare condition that occurs in pregnancies of identical twins that share one placenta.

TRAP sequence occurs in one  in 35,000 pregnancies overall. In TRAP sequence, one twin is developing normally while the other develops without a functioning heart and other body parts such as a head, arms or legs.

The goal of prenatal care is to minimize the risk of heart failure for the normally developing twin. Sadly, the other twin will not survive after birth since it does not have a functioning heart. Our Fetal Concerns Center will assess your pregnancy and work with you to develop a plan for your pregnancy which could include surgery, medication or other treatments.

Sometimes babies with certain health conditions require a special, planned delivery method so that they can immediately get the medical attention they need and make a more stable transition to life outside the womb.

The ex utero intrapartum treatment (EXIT) procedure is used with babies whose airways are obstructed by tumors or other fetal anomalies, such as congenital diaphragmatic hernia or congenital pulmonary airway malformation. It involves partially delivering the baby and keeping them attached to the placenta during the surgical repair, with the umbilical cord and placenta acting as life support. This complex procedure is available at only the most specialized centers, and the Fetal Concerns Center at Children’s Wisconsin was proud to perform the state’s first EXIT delivery in 2010.

An immediate postpartum access to cardiac therapies (IMPACT) delivery is used when a baby with severe heart defects (such as hypoplastic, with other complicating factors) faces life-threatening cardiovascular or respiratory problems as soon as they are disconnected from the placenta. In those cases, the baby is delivered via C-section in a cardiac operating room and then sent to an adjacent room for immediate cardiac catheterization or heart surgery. The experts in Children’s Wisconsin's Fetal Concerns Center and Herma Heart Institute have been collaborating on IMPACT deliveries since 2012.

This procedure replenishes a baby’s red blood cells when they have severe anemia. This is similar to a transfusion an adult with critically low blood might receive. It might be recommended if your baby’s red blood cell count dips too low. Fetal blood transfusions can prevent a baby’s anemia from progressing into a life-threatening condition. This procedure has been used to treat fetal anemia for decades and has a strong track record of success.