What Is Selective Fetal Growth Restriction?Selective Fetal Growth Restriction is diagnosed when 1 twin falls under the 10th percentile in weight for gestational age and there is more than 20% discordance between the twins weight in grams. It is then classified into type 1, 2 or 3 depending on the flow of blood in the umbilical cord. In type 1, the smaller twin’s cord flow is always positive, type 2 the smaller twin’s cord flow is absent, or reverse, and in type 3, the smaller twin’s cord flow is intermittent. You can move between the different types, and not much is known about long term outcomes, although recent research suggests there is an impact on the smaller twin.
The best treatment is unknown, with some centers doing laser surgery, and others choosing to perform selective reduction. However, an emerging consensus is close monitoring is possibly the best way to handle it. |
Diagnosing SFGR
Size Discordance: There is a size discordance of more than 20% and one twin is below the 10th percentile and one of the following:
Type 1: The cord flow is always positive in the smaller twin
Type 2: Absent, or reverse flow in the cord of the smaller twin
Type 3: Intermittent flow in the cord of the smaller twin
Other Signs: Sometimes there can be fluid discordances that don’t fit TTTS criteria.
Source: A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin - E Gratacós et al, 2007.
Type 1: The cord flow is always positive in the smaller twin
Type 2: Absent, or reverse flow in the cord of the smaller twin
Type 3: Intermittent flow in the cord of the smaller twin
Other Signs: Sometimes there can be fluid discordances that don’t fit TTTS criteria.
Source: A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin - E Gratacós et al, 2007.
More Information and Support
The Fetal Health Foundation – Selective Intrauterine Growth Restriction
Twins Trust – Growth Restrictions
Facebook Communities
TTTS Hope and Connections - Support for TTTS and SIUGR
International Clinical Trials
The TwinLife Study is looking into long-term outcomes for monochorionic twins inutero, and establishing if these discordances have an impact. The LEMON Study is looking into the long term outcomes for twins affected by SFGR.
Twins Trust – Growth Restrictions
Facebook Communities
TTTS Hope and Connections - Support for TTTS and SIUGR
International Clinical Trials
The TwinLife Study is looking into long-term outcomes for monochorionic twins inutero, and establishing if these discordances have an impact. The LEMON Study is looking into the long term outcomes for twins affected by SFGR.