Twin Anemia–Polycythemia Sequence in Two Monochorionic Twin Pairs Without Oligo-Polyhydramnios Sequence

Lopriore, E.; Middeldorp, J.M.; Oepkes, D.; Kanhai, H.H.; Walther, F.J.; Vandenbussche, F.P.H.A.

doi:10.1016/j.placenta.2006.01.010

« Previous Next »Placenta
Volume 28, Issue 1 , Pages 47-51, January 2007

Twin Anemia–Polycythemia Sequence in Two Monochorionic Twin Pairs Without Oligo-Polyhydramnios Sequence

E. Lopriore, MD
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
- Corresponding author. E. Lopriore, MD, Division of Neonatology, Department of Pediatrics, J6-S, Leiden University Medical Center, albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands. Tel.: +31-71-5262909; fax: +31-71-5248199.
J.M. Middeldorp, MD
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands
D. Oepkes, MD, PhD
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands
H.H. Kanhai, MD, PhD
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands
F.J. Walther, MD, PhD
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
F.P.H.A. Vandenbussche, MD, PhD
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands

Accepted 18 January 2006. published online 07 March 2006.

Abstract

Placental vascular anastomoses in monochorionic twins may lead to acute or chronic inter-twin transfusion. We report an uncommon form of chronic inter-twin transfusion, referred to as twin anemia–polycythemia sequence (TAPS), with severe anemia in one twin and polycythemia in the other, without the characteristically associated twin oligo-polyhydramnios sequence (TOPS) seen in the classical twin-to-twin transfusion syndrome (TTTS). The clinical course and placental characteristics of two pairs of monochorionic twins with TAPS born at, respectively, 33 and 34 weeks' gestation were reviewed. Serial fetal ultrasound examinations revealed no signs of TOPS. At birth, both donor twins were severely anemic requiring blood transfusion and both recipients were polycythemic, one requiring partial volume exchange transfusions. Inter-twin difference in reticulocyte counts was extremely high, suggesting a chronic form of inter-twin blood transfusion. Placental injection studies revealed a preponderance of very small (<1mm) arterio-venous anastomoses in one direction. In conclusion, chronic inter-twin transfusion may lead to an uncommon form of inter-twin transfusion, named TAPS, not associated with TOPS, resulting in severe fetal or neonatal hematological complications. We hypothesize that TAPS is mediated through minuscule unidirectional anastomoses. TAPS can be diagnosed antenatally with Doppler studies and postnatally by hemoglobin and reticulocyte measurements.