Learn More
 Twin to Twin Transfusion Syndrome (TTTS)
Minimize
What is Twin to Twin Transfusion Syndrome (TTTS)?
Twin to Twin Transfusion syndrome (TTTS) is a serious, progressive disease of the placenta where one twin donates blood and nutrients to his/her co-twin.  This happens in approximately 10-15% of identical twins that share a placenta.  Essentially, the baby who is donating (this baby is called the "donor") his/her blood is at risk of dehydration and anemia.  The other twin who is receiving the extra blood (this baby is called the "recipient") is at risk for volume overload which can lead to congestive heart failure in severe cases.
 
When and how is TTTS diagnosed?
TTTS is usually diagnosed by ultrasound between 16 and 24 weeks of pregnancy through a high-risk OB center.  The diagnosis of TTTS is made when the ultrasound reveals one twin (donor) to have an abnormally low level of amniotic fluid.  The sonographer or physician may refer to this baby as "stuck" or "saran-wrapped".  In addition, the other twin (recipient) demonstrates an excessive amount of amniotic fluid.  Some pregnant women with TTTS notice an extreme change in the fullness or tightness of their belly and/or uterine contractions resulting from the excess amniotic fluid around the recipient twin.
 
 
How do you decide how bad the condition is?
TTTS can be mild or severe, depending on how the babies are affected.  Each case is unique in presentation as well as in the course of disease progression.  TTTS has been divided into different stages to help determine when to intervene and by what method.
 
       Stage I:  This is the minimum criteria to technically be diagnosed with TTTS.  At this stage, the donor twin has oligohydramnios (a maximum vertical pocket of less than 2 cm) AND the recipient twin has polyhydramnios (a maximum vertical pocket of greater than 8-10 cm).
 
     At this stage, if there are no concerns about pre-term labor, intervention is usually not recommended.  However, the pregnancy should be closely monitored by a qualified Maternal-Fetal Medicine Specialist due to the unpredictable nature of the disease.
 
       Stage II:  The bladder on the donor twin is not visible during the course of the ultrasound exam.  This indicates that the bladder is empty and signals worsening dehydration of the donor twin. At this stage, intervention is recommended, as TTTS Stage II does not often improve on its own.
 
       Stage III:  At this stage, blood flow patterns (doppler studies) have become critically abnormal.  Blood flow patterns are measured in three areas of each twin;  the umbilical cord, the middle cerebral artery (a vessel in the brain) and the ductus venosus (a vessel near the liver).  These measurements give the physician a sense of how each baby is tolerating the progression of TTTS.  This stage requires intervention by laser photocoagulation.
 
       Stage IV: The recipient twin has developed swelling under the skin (hydrops) and appears to be in heart failure.   This is extremely critical and requires urgent intervention.   Laser photocoagulation may be attempted, but the chance of survival of the recipient twin may be low.
 
       Stage V:  One of the twins has died.  This can happen to either twin.  Thorough ultrasound examination of the survivor is important to ensure that this baby is not adversely affected.
 
What will happen to the babies without treatment?
TTTS is a progressive disorder.  If it is not treated and it continues to worsen, both babies will likely pass away (80-100% of the time).  Babies that survive a pregnancy with severe TTTS and no treatment have a 1 in 4 risk of brain damage because of lack of oxygen, blood and other nutrients.  This pregnancy may also be lost because the uterus gets overstretched from the polyhydramnios (excessive fluid), which can lead to preterm labor and miscarriage.
What is Twin to Twin Transfusion Syndrome (TTTS)?
Twin to Twin Transfusion syndrome (TTTS) is a serious, progressive disease of the placenta where one twin donates blood and nutrients to his/her co-twin.  This happens in approximately 10-15% of identical twins that share a placenta.  Essentially, the baby who is donating (this baby is called the "donor") his/her blood is at risk of dehydration and anemia.  The other twin who is receiving the extra blood (this baby is called the "recipient") is at risk for volume overload which can lead to congestive heart failure in severe cases.
 
When and how is TTTS diagnosed?
TTTS is usually diagnosed by ultrasound between 16 and 24 weeks of pregnancy through a high-risk OB center.  The diagnosis of TTTS is made when the ultrasound reveals one twin (donor) to have an abnormally low level of amniotic fluid.  The sonographer or physician may refer to this baby as "stuck" or "saran-wrapped".  In addition, the other twin (recipient) demonstrates an excessive amount of amniotic fluid.  Some pregnant women with TTTS notice an extreme change in the fullness or tightness of their belly and/or uterine contractions resulting from the excess amniotic fluid around the recipient twin.
 
 
How do you decide how bad the condition is?
TTTS can be mild or severe, depending on how the babies are affected.  Each case is unique in presentation as well as in the course of disease progression.  TTTS has been divided into different stages to help determine when to intervene and by what method.
 
       Stage I:  This is the minimum criteria to technically be diagnosed with TTTS.  At this stage, the donor twin has oligohydramnios (a maximum vertical pocket of less than 2 cm) AND the recipient twin has polyhydramnios (a maximum vertical pocket of greater than 8-10 cm).
 
     At this stage, if there are no concerns about pre-term labor, intervention is usually not recommended.  However, the pregnancy should be closely monitored by a qualified Maternal-Fetal Medicine Specialist due to the unpredictable nature of the disease.
 
       Stage II:  The bladder on the donor twin is not visible during the course of the ultrasound exam.  This indicates that the bladder is empty and signals worsening dehydration of the donor twin. At this stage, intervention is recommended, as TTTS Stage II does not often improve on its own.
 
       Stage III:  At this stage, blood flow patterns (doppler studies) have become critically abnormal.  Blood flow patterns are measured in three areas of each twin;  the umbilical cord, the middle cerebral artery (a vessel in the brain) and the ductus venosus (a vessel near the liver).  These measurements give the physician a sense of how each baby is tolerating the progression of TTTS.  This stage requires intervention by laser photocoagulation.
 
       Stage IV: The recipient twin has developed swelling under the skin (hydrops) and appears to be in heart failure.   This is extremely critical and requires urgent intervention.   Laser photocoagulation may be attempted, but the chance of survival of the recipient twin may be low.
 
       Stage V:  One of the twins has died.  This can happen to either twin.  Thorough ultrasound examination of the survivor is important to ensure that this baby is not adversely affected.
 
What will happen to the babies without treatment?
TTTS is a progressive disorder.  If it is not treated and it continues to worsen, both babies will likely pass away (80-100% of the time).  Babies that survive a pregnancy with severe TTTS and no treatment have a 1 in 4 risk of brain damage because of lack of oxygen, blood and other nutrients.  This pregnancy may also be lost because the uterus gets overstretched from the polyhydramnios (excessive fluid), which can lead to preterm labor and miscarriage.
Twin to Twin Transfusion Syndrome | TRAP Sequence | Selective Intrauterine Growth Restriction (SIUGR)
Copyright 2009 by Evergreen Fetal Therapy
Terms Of Use | Privacy Statement