This document discusses twin-twin transfusion syndrome (TTTS), which occurs in some monochorionic twin pregnancies when blood vessels between the twins' placentas allow unbalanced blood flow from one twin to the other. This can cause one twin to become anemic and growth restricted (the donor) while the other becomes overloaded (the recipient). The syndrome is diagnosed when one twin shows polyhydramnios while the other shows oligohydramnios. Management depends on gestational age and disease stage, and may include amnioreduction, laser ablation of connecting vessels, or septostomy. Without treatment, both twins are at high risk of complications or death.

1. T W I N T O T W I N
T R A N S F U S I O N
S Y N D R O M E

2. I N T R O D U C T I O N
• Vascular communications exist between the two
placentas in all MC twins,which are usually artery to
artery vein to vein.
• As the pressure is equal on both sides with no gradient,
the blood supply to the foetuses is not compromised.
• But in TTTS the artery of one foetus communicates with
the vein of the other foetus,giving rise to pressure
gradient.
• Thus blood flows unidirectionally from one foetus to the
other resulting in hyper perfusion of the recipient twin
and hypo perfusion of the donor twin.

3. • The donor becomes
anaemic and its
growth maybe
restricted, while the
recipient becomes
polycythemic and may
develop circulatory
overload manifest as
hydrops.
• One portion of the
placenta appears pale
compared to the other.

4. P R E V A L E N C E
• The prevalence of this condition is approximately 1 to
3 per 10,000 births.

5. P A T H O P H Y S I O L O G Y
• Chronic TTTS results from unidirectional flow through
arteriovenous anastomoses.
• Deoxygenated blood (donor) from placental artery is
pumped into a cotyledon shared by the recipient.
• Once oxygen exchange is completed in chorionic villus,
the oxygenated blood leaves the cotyledon via a
placental vein of the recipient twin.
• Unless compensated, typically through arterioarterial
anastomoses—this unidirectional flow leads to an
imbalance in blood volumes.

6. • TTTS is chronic and there is significant vascular volume
differences between the twins.
• However, in MC twin pregnancy complicated by this
syndrome, there is no difference in the haemoglobin
concentrations between the donor and recipient twins.
• The syndrome presents in mid pregnancy wherein the
donor foetus becomes oliguric from decreased renal
perfusion presenting with oligohydramnios and recipient
foetus showing polyhydramnios due increased urine
production

7. Changes in the donor and recipient twins
D O N O R T W I N
- Oligohydramnios
- Foetal growth restriction
- Pulmonary hypoplasia
- Contractures
R E C I P I E N T T W I N
- Polyhydramnios
- Cardiac failure

8. D I A G N O S I S
• TTTS is diagnosed based on two criteria:
✤ presence of a monochorionic diamnionic pregnancy
✤ hydramnios defined if the largest vertical pocket is >8cms in one
twin and oligohydramnios defined if the largest vertical pocket is
<2cms in the other twin.
• Once identified, TTTS is typically staged by the Quintero staging
system:
✴ Stage I—discordant amnionic fluid volumes, but urine is still
visible sonographically within the bladder of the donor twin.
✴ Stage II—criteria of stage I, but urine is not visible in the donors
bladder.
✴ Stage III—criteria of stage II and abnormal Doppler studies of
the umbilical artery, ductus venosus, or umbilical vein.
✴ Stage IV—ascites or frank hydrops in either vein.
✴ Stage V—demise of either fetes.

9. S T U C K T W I N
• Also known as
polyhydramnios-
oligohydramnios
syndrome— “POLY-OLI”
• This is a condition wherein
the visual absence of
amniotic fluid in the donor
sac causes the dividing
membrane to attach to the
foetal body thereby
preventing foetal
movements— “stuck twin”.

10. M A N A G E M E N T
• It greatly depends on gestation age and the stage of
the disease.
• Serial amnioreduction- removal of amniotic fluid from
the recipient twin by amniocentesis under ultrasonic
guidance.
• Laser ablation of communicating vessels using
foetoscope.
• Septostomy- puncturing of the septum between the
two sacs to create an iatrogenic mono amniotic sac.
• Selective foeticide- used in TTTS that occurs before
20weeks of gestation.

11. A M N I O R E D U C T I O N
L A S E R A B L A T I O N

12. THANK YOU