Laser ablation of the placenta
.png/:/cr=t:0%25,l:0%25,w:100%25,h:100%25/rs=w:1209,cg:true)
In some identical twin pregnancies that share a placenta (monochorionic twins), the twins are connected by blood vessel connections on the surface of the placenta. These shared vessels can cause blood to flow unevenly between the twins, leading to serious conditions such as:
- Twin–Twin Transfusion Syndrome (TTTS): One twin (“donor”) gives too much blood, while the other (“recipient”) receives too much.
- Twin Anemia–Polycythemia Sequence (TAPS): A slower, unbalanced blood exchange causes one twin to become anemic and the other to have too many red blood cells.
- Twin Reversed Arterial Perfusion (TRAP) sequence: One twin (the “pump twin”) supplies blood to a non-viable twin, placing dangerous strain on the healthy twin’s heart.
Without treatment, these conditions can lead to heart failure, preterm birth, brain injury, or loss of one or both babies
(Pic: Dr. Martha Monson and Dr. Jan Byrne performing laser ablation for TTTS)
What is laser ablation of the placenta?
Laser ablation is a minimally invasive fetal procedure that treats the root cause of these conditions by permanently closing the abnormal blood vessel connections between the twins.
The goal is to:
- Separate the twins’ blood supplies
- Allow each baby to receive blood only from their own part of the placenta
- Reduce strain on the heart and improve survival and long-term outcomes
How is the procedure done?
- The procedure is performed under ultrasound guidance
- A small camera (fetoscope) is inserted through the mother’s abdomen into the amniotic sac
- The shared placental blood vessels are carefully identified
- A laser fiber is used to seal the abnormal vessel connections
- In TTTS, excess amniotic fluid may also be drained at the end of the procedure
There are no incisions on the uterus large enough to be felt later, and the placenta remains in place to continue supporting the pregnancy
What happens after the procedure?
- Most patients are monitored in the hospital for 1–2 days
- Ongoing care includes frequent ultrasounds to assess:
- Growth of both babies
- Amniotic fluid levels
- Heart function
- Signs of recurrence or complications
- Delivery timing depends on pregnancy progress and clinical findings
Many families may be able to continue care with their local obstetric and maternal–fetal medicine teams, with close coordination with our fetal center
What are the benefits?
- Treats the underlying cause, not just symptoms
- Improves survival for one or both twins
- Reduces the risk of:
- Heart failure
- Severe prematurity
- Neurologic injury
- Allows the pregnancy to continue more safely
What are the risks?
As with any fetal procedure, there are risks, including:
- Preterm rupture of membranes
- Preterm labor
- Bleeding or infection
- Loss of one or both twins (this depends on disease severity and gestational age)
These risks are carefully weighed against the very high risks of no treatment in severe TTTS, TAPS, or TRAP, and should be discussed with our MFM interventionists prior to surgery
