TTTS
The etiology of TTTS appears to result from a net
unbalanced flow of blood between two MC fetuses
through placental vascular communications, which
results in a donor twin and a recipient twin. Although
actual documentation of the unbalanced blood flow
remains elusive [5], vascular anastomoses might be
responsible for the development of TTTS if the vascular
design is such that it forces a net flow from
donor to recipient [5]. Alternatively, vascular anastomoses
might play a passive role in the development
of the syndrome, but nonetheless allow its
development. This is the case with MC twins who
are discordant for congenital heart disease, cardiomyopathies,
cord anomalies, or other conditions
associated with uneven hemodynamic competence
[6]. When the onset of this condition occurs before
26 weeks of gestation, there is a significant associated
risk of fetal loss, perinatal death, and subsequent
handicap in survivors [7]. If untreated at its
early onset, severe TTTS has a dismal prognosis,
with perinatal mortality rates > 90% [8], and >30%
of survivors suffering from associated neurodevelopmental
anomalies [8].