Understanding the Stages of TTTS

Twin-to-twin transfusion syndrome (TTTS) can be divided into “stages” to help identify the severity and the most appropriate treatment option.
  • Stage I: A small amount of amniotic fluid (oligohydramnios) is found around the donor twin and a large amount of amniotic fluid (polyhydramnios) is found around the recipient twin. At this stage, we usually recommend that the pregnancy is closely observed for further deteriorations.
  • Stage II: In addition to the description above, the ultrasound is not able to identify the bladder in the donor twin. This is an indication that laser photocoagulation may be helpful.
  • Stage III: In addition to the characteristics of Stages I and II, there is abnormal blood flow in the umbilical cords of the twins. Laser photocoagulation is recommended in this situation.
  • Stage IV: In addition to all of the above findings, the recipient twin has swelling under the skin and appears to be experiencing heart failure (fetal hydrops). Laser photocoagulation may be attempted, but the chance of survival in this stage is lower.
  • Stage V: In addition to all of the above findings, one of the twins has died. Usually the donor twin is the twin to die first, but it can happen to either.