Journal of Clinical Images and Medical Case Reports

ISSN 2766-7820
Case Report - Open Access, Volume 2

Twin anemia polycythemia sequence (TAPS)

Joana Lira1*; Joana Soares Reis1; Conceição Costa2 ; António Vinhas da Silva2

1 Pediatrics Department, Centro Hospitalar de Vila Nova de Gaia/Espinho, Vila Nova de Gaia, Portugal.

2 Neonatology Unit, Pediatrics Department, Centro Hospitalar de Vila Nova de Gaia/Espinho, Vila Nova de Gaia, Portugal.

*Corresponding Author: Joana Terroso Lira
Vila Nova de Gaia and Espinho Hospital Center, Pediatrics Medical Service, Rua Dr. Francisco Sá Carneiro, 4400-129 Vila Nova de Gaia, Portugal.
Email: [email protected]

Received : Nov 25, 2021

Accepted : Dec 14, 2021

Published : Dec 21, 2021

Archived :

Copyright : © Lira JT (2021).

Keywords: newborn; fetofetal transfusion; anemia; polycythemia; neonatology.

Abbreviations: AS: Apgar Score; Hb: Hemoglobin; TAPS: Twin Anemia Polycythemia Sequence; TTTS: Twin To Twin Transfusion Syndrome.

Citation: Lira J, Reis J S, Costa C, Silva AVD. Twin anemia polycythemia sequence (TAPS). J Clin Images Med Case Rep. 2021; 2(6): 1498.

Clinical image description

A 33-year-old monochorionic twin gravida was subjected to a cesarean section at 31 weeks’ gestation due to preeclampsia. The pregnancy was otherwise uneventful.

The first-born infant (Figure 1) was pale, weighed 1095 g and had an AS of 8/9/9; the second-born twin (Figure 2) was plethoric, weighed 1465 g and had an AS of 9/10. Hb values for twin 1 and twin 2 were 5.8 g/dL and 24.9 g/dL and a reticulocyte count of 11.25% and 6.09%, respectively. The anemic infant was hypovolemic requiring two blood transfusions on day 1. A partial volume exchange transfusion was required for the polycythemic twin, since hematocrit increased to 73.7% on day 1 despite IV hydration.

Figure 1: Anemic twin.

A significant skin coloration difference between twins at birth should raise suspicion for TAPS, a recently described form of chronic feto fetal transfusion that can occur spontaneously in 3 to 5% of monochorionic twin pregnancies [1] or after laser ablation of placental anastomoses in TTTS [2]. It results of small AV anastomoses that allow slow unidirectional flow of blood from a donor to a recipient twin causing anemia in the donor and polycythemia in the recipient with normal fluid volumes in both gestational sacs [3].

Prenatal diagnosis is based on measurement of the middle cerebral artery peak systolic velocity (that is usually increased in the anemic twin and decreased in the polycythemic twin), but is frequently missed. Large intertwin differences in Hb values (>8 g/dl), reticulocyte count ratio >1.7 or small vascular placental anastomoses without oligopolyhydramnios are essential for postnatal diagnosis [3]. Clinical presentation at birth is largely variable from a simple hb differential to severe brain injury and even death. On a long-term, TAPS seems to be associated with severe neurodevelopmental impairment and deafness, especially for the donor twin [1].

Figure 2: Polycythemic twin.

Author contribution statement: All authors participated inthe treatment of this case, and the first author drafted the manuscript. All authors read and approved the final manuscript.

Conflict of interest: The authors declare no conflicts of interest.

Funding statement: This study has no funding.


  1. Tollenaar LSA, Lopriore E, Slaghekke F, Oepkes D, Middeldorp JM, et al. High risk of long term neurodevelopmental impairment in donor twins with spontaneous twin anemia polycythemia sequence. Ultrasound Obstet Gynecol. 2020; 55: 39-46.
  2. Lopriore E, Middeldorp JM, Oepkes D, Kanhai HH, Walther FJ, Vandenbussche FP. Twin anemia polycythemia sequence in two monochorionic twin pairs without oligo polyhydramnios sequence. Placenta. 2007; 28: 47-51.
  3. Slaghekke F, Kist WJ, Oepkes D, Pasman SA, Middeldorp JM, Klumper FJ, et al. Twin anemia-polycythemia sequence: Diagnostic criteria, classification, perinatal management and outcome. Fetal diagnosis and therapy. 2010; 27:181-90.