Case Presention

Twin-to-twin transfusion syndrome (stuck twin)

Mrs. Vidya, 30yr old Primi 1st visit at 21-22 weeks.

Early pregnancy scan at 6 weeks: only a single intra uterine gestational sac with a fetal pole was identified.



Repeat scan at 12-13 weeks :2 fetal poles within a single sac with an intervening membrane.



No comments available on Chorionicity
The Mid Trimester scan showed.

Fetus A the smaller stuck twin, GA was 22 weeks
showed 18-19 weeks with a growth lag of 4 weeks.



Absolutely no liquor around, so much so that identifications of the membrane itself was with great difficulty.

Bladder was empty, Stomach undistended and the fetus stuck to the anterior uterine wall.
It also showed an absent AEDV in both UMB & MCA



Fetus B.
Corresponded to the period of GA in growth, which had a gross poly amnios of AF1 45 cms and persistently full bladder.



And with a single placenta, the final impression was T-TTS with stuck twin phenomenon

The option of management in such cases would be either

• selective feticide with intra cardiac instillation of Normal saline of smaller
twin when the GA < 25 wks.

• Laser coagulation & obliterate communicating vessels.

• Serial amniocentesis & relieve poly amnios.

In this case
we attempted reduction of AFV by serial amnio reduction.

1st tap was done at 23 weeks 500cc was drained.

Refilling was detected in one week.

SHOULD WE HAVE DRAINED MORE AT THIS SITTING ?

Literature review shows that for every 10 cm increase in AFV ,one litre to be removed
Going by this calculation,serial reduction of 2500 cc ought to have been done & a megre amount of 500 cc was not enough.

at 24 weeks
& 26 weeks about 2500 cc was drained at each visit.

After 3rd reduction :
The growth profile improved.

Fetus A	Fetus B

• The procedure can also create a common between 2 sacs, so that    subsequently the balance remains

• Outcome:
        Patient was delivered by LSCS and the fetii showed

        Birth weight A: 1.6 gm B : 2.2gm ( difference of > 20 % )
        Hb : 11 gm & 17 gm ( difference of 5 gm )

        Proof of TTTS by placentation histopathology to evidence         anastomosis is difficult and in conclusive

        Neonatal period was uneventful ,babies not needing incubator or         intensive neonatal care

        Mrs. Vidya & her husband carried their bundles of joy home

More about
Twin to Twin Transfusion Syndrome

Knowledge of the embryological sequence for chorion and amnion formation is critical to assessing multifetal gestation with USG.

Where ever there is single placenta there is a sharing of circulation and unbalanced shunting of blood from one to another through mostly Arteriovenous communication will give rise to a situation of Twin to Twin Transfusion Syndrome (TTTS) with discordant fetal size & Amniotic fluid volume.

TTTS is unique to monochorionic twins. The incidence being as high as 35% in Monochorionic as against 1% with Dichorionic twins.

Complications & mortality is more in these cases and therefore counseling for prognosis would be different when a Monochorinic twin gestation has been identified.

As against these if there are 2 placenta (i.e.) Dichorionic twins this can be easily identified when the placenta are in different location as seen here

The confusion arises if the placenta lie one beside the other and the best opportunity to distinguish and confirm the chorionicity is in the I trimester of pregnancy.

Where a DC twin is identified the Lambada sign.

In a DC twin, the chorion & the amnion of each twin reflect away from the fused placenta to form the inter twin membrane. A potential space exists in this inter twin membrane which can be filled by the proliferating placental villi giving rise to the twin peak sign.

In Monochorionic diamniotic twins the inter twin membrane is composed of only 2 amnions. A single chorion forms an impenetrable barrier for extension of the chorionic villi into the membrane.

It is likely that this MC twin may develop a TTTS
the USG diagnosis of TTTS can be made by picking up

Twin with discordant growth
AC difference of > 20mm.
Poly amnios of larger twin, which may develop hydrops later.
Oligoamnios of the smaller twin resulting in IUD.

Stuck twin phenomenon occurs in 8% of such cases.

Deducing Zygocity from U/S observations – II trimester