What is a radio-frequency ablation (RFA)?
RFA is a procedure utilized to stop the blood flow in an abnormal fetus. It uses a small needle device that is inserted by ultrasound guidance to identify the insertion of the umbilical cord to the fetus. The needle is turned "on" until there is no more blood flow going to the fetus. The advantage of this technique is the small size of the RFA needle which minimizes the risks of preterm labor. The remains of the abnormal fetus will either become smaller or pass during delivery.
Which conditions are treated with radio-frequency ablation?
RFA procedures are typically utilized in abnormal twin pregnancies. Your doctors may have identified a condition in which one abnormal twin is threatening the life of the other normal twin. In these situations, it may be necessary to stop the blood flow to the abnormal twin. RFA has been utilized in many obstetrical diseases but has mostly been performed for Twin Reverse Arterial Perfusion Sequence (TRAP). For twin pregnancies with an acardiac/acephalic twin, the abnormal fetus can be a cardiac burden on the normal twin and cause heart failure. As a result, RFA can be utilized to stop the connection between the two fetuses.
The recommendation to perform RFA for TRAP sequence will be determined by your team of doctors at the Center.
What special considerations should be made at time of delivery?
Type of delivery - Typically, RFA procedures do not require Cesarean delivery. The need for this fetal intervention should not impact your type of delivery. The delivery plan should be carefully discussed between the mother and the obstetrician.
Place of delivery - If all the prenatal monitoring suggests that your baby is doing well, the baby can be delivered at the hospital of your choice. However, the hospital should be prepared to handle any intensive care of your newborn and have a neonatal intensive care unit with the capability to provide specialized care.
Time of delivery - Unless there are signs of fetal heart failure due to the TRAP sequence or complications from the RFA procedure, there is no reason to intentionally induce early delivery. After the RFA procedure, your pregnancy will be continual to be monitored. If your baby is far enough along to survive delivery, the team at the Center may recommend early delivery for pregnancies that appear to be in danger.
What will happen at the radio-frequency ablation procedure?
The entire team will carefully plan for the RFA procedure with preparation to handle all potential complications. Generally, the procedure is performed under IV sedation and local anesthesia. Your doctors will repeat a detailed ultrasound to confirm the problem and identify the abnormal twin and identify a pathway for the RFA needle that avoids the other twin and the placenta. A small skin incision is made to allow the placement of the RFA needle. The RFA needle is activated until blood flow is stopped in the abnormal twin. On occasion, the RFA procedure cannot be performed with a small skin incision due to the location of the fetuses and placenta in the uterus. In these situations, the procedure requires a larger incision to expose the uterus in order to provide a safe window for the RFA needle.
The RFA procedure is performed in the operating room with all the special equipment necessary to ensure the safety of you and your baby. Afterwards, the mother will be admitted to the Women's Center to monitor for preterm labor and complications at Children's Memorial Hermann Hospital.
What will happen at birth?
Your pregnancy should continue normally. The normal twin can be delivered without special considerations. Although your team of doctors at the Center will continue to closely follow your pregnancy, the plan for delivery can be made with your personal obstetrician.
What are the long-term outcomes and considerations?
Utilizing RFA to treat TRAP sequence has been shown to be extremely effective. Our colleagues at the University of California, San Francisco have reported a success rate of greater than 90% survival of the normal twin with an average gestational age of delivery of 35 weeks. Although not every pump twin survives this condition or the procedure, there have not been any reported harmful long-term outcomes regarding RFA and pregnancies with TRAP sequence.
Contact the Texas Fetal Center to make an appointment with a high-risk pregnancy doctor.