Limited evidence suggests the best way to save babies with twin-to-twin transfusion syndrome is to perform laser treatment to the placenta.
Identical twins occur in about one in 320 pregnancies. Sometimes identical twins share the same placenta and blood flow, and the proportion of blood shared between the twins is usually equal. Twin-to-twin transfusion syndrome happens when the blood flow is uneven and passes from one twin (the donor) to the other (the recipient). This can happen when the placenta has deep artery-to-vein connections. The donor twin usually has very little amniotic fluid, and frequently does not grow well and is very small. The recipient twin has excessive amniotic fluid, and often has a distended bladder and other medical problems. The risk of death for both twins is high, around 80% if there is no treatment. There is also risk of physical or neurological damage to both twins if they survive. Various options for treatment exist. These include (1) the repeated removal of excessive amniotic fluid (amnioreduction); (2) laser treatment of the abnormal vessels in the placenta (endoscopic laser surgery); (3) puncture of the membrane between the twins (septostomy); and (4) the selective ending of one twin's life (selective feticide). The review found two trials, involving 213 women and 430 babies. There were no studies on laser treatment versus puncturing the membrane, nor on selective feticide. The evidence showed that laser treatment was associated with fewer babies dying when compared to removing the excess amniotic fluid. However, where there is insufficient expertise to perform laser surgery, amnioreduction is then the treatment of choice. None of the studies assessed morbidity for the mother. Further research is needed on mild forms of the problem.