Hematological disorders at birth in complicated monochorionic twins

Figures & data

Table 1. Differences between TTTS, TAPS, and acute TTTS.

	Pathogenesis	Timing of diagnosis and criteria	Hematological disorders at birth
TTTS	Chronic inter-twin transfusion through anastomoses, usually during second trimester of pregnancy	Antenatal; oligo-polyhydramnios sequence on ultrasound	Inter-twin Hb discordance might occur depending on antenatal treatment
TAPS	Chronic inter-twin transfusion through small (diameter <1 mm) anastomoses, may occur during second or third trimester of pregnancy	Antenatal; discordant MCA-PSV values on Doppler ultrasound, or postnatal; inter-twin Hb discordance and large inter-twin reticulocyte count ratio or small AV-anastomoses <1 mm	Large inter-twin Hb difference (>8 g/dL) Reticulocytosis in the donor and inter-twin reticulocyte count ratio >1.7 Polycythemia in the recipient Increased risk of thrombocytopenia in recipient
Acute peripartum TTTS	Acute inter-twin transfusion through anastomoses during delivery	Postnatal; inter-twin Hb discordance without inter-twin difference in reticulocyte count	Large inter-twin Hb difference >8 g/dL No reticulocytosis in donor Reticulocyte count ratio <1.7

Hb: Hemoglobin; TTTS: twin–twin transfusion syndrome; TAPS: twin anemia–polycythemia sequence.

Table 2. Hemoglobin levels and reticulocyte counts at birth, and presence of anemia or polycythemia.

	Hb level (g/dL)		Reticulocyte count (g/dL)		Anemian (%)^a	Polycythemian (%)^b
	Donors	Recipients	Donors	Recipients
TTTS – conservative management N =62	13.9 ± 3.5 n = 43	18.4 ± 3.6 n = 42	83.9 ± 50.1 n = 33	76.7 ± 31.0 n = 33	14 (33%) n = 43	10 (24%) n = 42
TTTS – complete laser N =357	16.8 ± 2.9 n = 245	17.1 ± 2.5 n = 257	67.3 ± 35.1 n = 198	64.6 ± 28.4 n = 201	13 (5%) n = 251	2 (1%) n = 252
TTTS – incomplete laser N=47	11.6 ± 5.0 n = 46	20.1 ± 3.6 n = 45	127.7 ± 88.6 n = 40	56.8 ± 31.1 n = 39	26 (55%) n = 47	16 (35%) n = 46
Spontaneous TAPS N=27	9.4 ± 4.7 n = 25	21.6 ± 3.7 n = 26	175.2 ± 128.8 n = 24	46.3 ± 21.5 n = 24	19 (83%) n = 23	13 (54%) n = 24
Acute peripartum TTTS N=12	13.5 ± 4.5 n = 12	20.7 ± 4.0 n = 12	52.4 ± 10.5 n = 9	53.6 ± 12.3 n = 9	3 (27%) n = 11	3 (27%) n = 11

Values given as mean ± SD.

^aAnemia at birth defined as low hemoglobin level requiring a blood transfusion on day 1.

^bPolycythemia at birth defined as an increased hematocrit requiring a partial exchange transfusion on day 1.

N refers to numbers of twin pairs; n refers to number of neonates; TTTS: twin–twin transfusion syndrome.

Figure 1. Anemia (needing blood transfusion) and/or polycythemia (needing PET) at birth in complicated monochorionic twins.