Antenatal management of twin-twin transfusion syndrome and twin anemia-polycythemia sequence

Figures & data

Figure 1. (Full color available online) Uncomplicated monochorionic twin placenta after color dye injection showing large vascular anastomoses. Arteries are injected with blue and green dye and veins are injected with pink and yellow dye. Arterio-venous anastomoses are indicated with white arrows, an arterio-arterial anastomosis is indicated with a blue arrow and a veno-venous anastomosis is indicated with a green arrow.

Figure 2. (Full color available online) TTTS placenta treated with the Solomon technique in which a laser coagulation line is clearly visible along the vascular equator.

Table 1. Differences between TTTS and TAPS.

	TTTS	TAPS
Pathogenesis	Transfusion through anastomoses	Transfusion through small anastomoses
Incidence	10%	Spontaneous TAPS: 1–5%
		Post-laser TAPS: up to 16%
Prenatal diagnosis	Oligo-polyhydramnios on prenatal US	Abnormal US Dopplers: MCA-PSV ≥1.5 MoM in donor & ≤1.0 MoM in recipient, without twin oligo-polyhydramnios sequence
Postnatal diagnosis	–	Intertwin Hb difference ≥8 g/dL
		AND at least one of the following:
		Reticulocyte count ratio >1.7
		Small AV-anastomoses (diameter < 1 mm)
Antenatal staging	Stage 1:	Stage 1:
	Donor DVP <2 cm, recipient DVP >8 cm, DVP >10 cm (≥20 weeks)	MCA-PSV ≥1.5 MoM & ≤1.0 MoM
	Stage 2:	Stage 2:
	Donor: no bladderfilling, recipient: full bladder	MCA-PSV ≥1.7 MoM & ≤0.8 MoM
	Stage 3:	Stage 3:
	Doppler abnormalities	Doppler abnormalities
	Stage 4:	Stage 4:
	Hydrops	Hydrops
	Stage 5:	Stage 5:
	IUFD	IUFD

US: Ultrasound; DVP: deepest vertical pocket; MCA-PSV: middle cerebral artery-peak systolic velocity; MoM: multiples of the median; Hb: hemoglobin; IUFD: intrauterine fetal demise; TAPS: twin anemia–polycythemia sequence; TTTS: twin–twin transfusion syndrome.

Figure 3. (Full color available online) TAPS placenta showing a few minuscule arterio-venous anastomoses (white arrows) and a minuscule arterio-arterial anastomosis (blue arrow). All anastomoses have a diameter < 1 mm.