Monochorionic (MC) twin complication with chronic, slow, unbalanced blood transfusion from donor (D) → recipient (R) twin
Most common after laser therapy for twin-twin transfusion syndrome (TTTS)
May occur spontaneously; develops > 26 weeks in previously uncomplicated MC twins
Spontaneous TAPS can coexist with TTTS
Isolated TAPS much rarer
IMAGING
General Features
Ultrasonographic Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Staging, Grading, & Classification
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
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Selected References
Tollenaar LSA et al: Spontaneous twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 249 cases. Am J Obstet Gynecol. 224(2):213.e1-11, 2021
Wang X et al: Longer distance between umbilical cord insertions is associated with spontaneous twin anemia polycythemia sequence. Acta Obstet Gynecol Scand. 100(2):229-34, 2021
Araújo Pereira J et al: Twin anemia polycythemia sequence. N Engl J Med. 382(6):e9, 2020
Han SJ et al: Short- and long-term outcomes of preterm spontaneous twin anemia-polycythemia sequence. J Perinat Med. ePub, 2020
Khalil A et al: Consensus diagnostic criteria and monitoring of twin anemia-polycythemia sequence: Delphi procedure. Ultrasound Obstet Gynecol. 56(3):388-94, 2020
Liu B et al: Performance of antenatal diagnostic criteria of twin-anemia-polycythemia sequence. J Clin Med. 9(9), 2020
Mao Q et al: Discordant placental oxygenation and autophagy in twin anemia-polycythemia sequence (TAPS). Placenta. 90:9-17, 2020
Shanahan MA et al: Placental anatomy and function in twin gestations. Obstet Gynecol Clin North Am. 47(1):99-116, 2020
Ting YH et al: Outcomes of radiofrequency ablation for selective fetal reduction in complicated monochorionic pregnancies performed before 16 gestational weeks and thereafter. Ultrasound Obstet Gynecol. ePub, 2020
Tollenaar LSA et al: Post-laser twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 164 cases. J Clin Med. 9(6), 2020
Tollenaar LSA et al: High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 55(1):39-46, 2020
Tollenaar LSA et al: Prevalence of placental dichotomy, fetal cardiomegaly and starry-sky liver in twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 56(3):395-9, 2020
Tollenaar LSA et al: Treatment and outcome of 370 cases with spontaneous or post-laser twin anemia-polycythemia sequence managed in 17 fetal therapy centers. Ultrasound Obstet Gynecol. 56(3):378-87, 2020
Visser GL et al: Leukocyte counts and other hematological values in twin-twin transfusion syndrome and twin anemia-polycythemia sequence. Fetal Diagn Ther. 47(2):123-8, 2020
Xu J et al: The utility of MRI for measuring hematocrit in fetal anemia. Am J Obstet Gynecol. 222(1):81.e1-13, 2020
Zhao D et al: Evaluation of color difference in placenta with twin anemia polycythemia sequence. J Vis Exp. 2020
Bahtiyar MO et al: In utero partial exchange transfusion combined with in utero blood transfusion for prenatal management of twin anemia-polycythemia sequence. Fetal Diagn Ther. 45(1):28-35, 2019
Hill KM et al: Intrauterine interventions for the treatment of twin anemia-polycythemia sequence: a systematic review. J Obstet Gynaecol Can. 41(7):981-91, 2019
Jha P et al: US evaluation of twin pregnancies: importance of chorionicity and amnionicity. Radiographics. 39(7):2146-66, 2019
Nicholas LD et al: Twin anemia-polycythemia sequence and routine monitoring practices amongst maternal-fetal medicine specialists in the United States: an initial investigation. J Perinat Med. 47(4):388-92, 2019
Nicholas L et al: Dispelling myths about antenatal TAPS: a call for action for routine MCA-PSV doppler screening in the United States. J Clin Med. 8(7), 2019
Tavares de Sousa M et al: Role of fetal intertwin difference in middle cerebral artery peak systolic velocity in predicting neonatal twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 53(6):794-7, 2019
Tollenaar LSA et al: Improved prediction of twin anemia-polycythemia sequence by delta middle cerebral artery peak systolic velocity: new antenatal classification system. Ultrasound Obstet Gynecol. 53(6):788-93, 2019
Tollenaar LSA et al: Twin-twin transfusion syndrome with anemia-polycythemia: Prevalence, characteristics, and outcome. J Clin Med. 8(8), 2019
Bamberg C et al: Quantified discordant placental echogenicity in twin anemia-polycythemia sequence (TAPS) and middle cerebral artery peak systolic velocity. Ultrasound Obstet Gynecol. 52(3):373-77, 2018
Persico N et al: Fetal Doppler changes 1 week after endoscopic equatorial laser for twin-to-twin transfusion syndrome: a longitudinal study. Prenat Diagn. 38(5):344-48, 2018
De Paepe ME et al: Redness discordance in monochorionic twin placentas: correlation with clinical and placental findings. Placenta. 60:54-60, 2017
Tollenaar LSA et al: Can color difference on the maternal side of the placenta distinguish between acute peripartum twin-twin transfusion syndrome and twin anemia-polycythemia sequence? Placenta. 57:189-93, 2017
Fishel-Bartal M et al: Can middle cerebral artery peak systolic velocity predict polycythemia in monochorionic diamniotic twins? Evidence from a prospective cohort study. Ultrasound Obstet Gynecol. 48(4):470-5, 2016
Guenot C et al: Fetal intra-peritoneal transfusion for the management of very early spontaneous twin anemia-polycythemia sequence in an obese patient with a whole anterior placenta. Twin Res Hum Genet. 19(2):154-7, 2016
Hiersch L et al: Amniotic fluid discordance in monochorionic diamniotic twin pregnancies is associated with increased risk for twin anemia-polycythemia sequence. Prenat Diagn. 36(12):1099-103, 2016
Slaghekke F et al: Antenatal management of twin-twin transfusion syndrome and twin anemia-polycythemia sequence. Expert Rev Hematol. 9(8):815-20, 2016
Stagnati V et al: Inter-twin discrepancy in middle cerebral artery peak systolic velocity and pregnancy outcome in monochorionic diamniotic twin pregnancies. Ultrasound Obstet Gynecol. 48(1):66-71, 2016
Tollenaar LS et al: Twin anemia polycythemia sequence: current views on pathogenesis, diagnostic criteria, perinatal management, and outcome. Twin Res Hum Genet. 19(3):222-33, 2016
Bahtiyar MO et al: The North American Fetal Therapy Network consensus statement: prenatal surveillance of uncomplicated monochorionic gestations. Obstet Gynecol. 125(1):118-23, 2015
Emery SP et al: The North American Fetal Therapy Network Consensus Statement: management of complicated monochorionic gestations. Obstet Gynecol. 126(3):575-84, 2015
Emery SP et al: The North American Fetal Therapy Network Consensus Statement: prenatal management of uncomplicated monochorionic gestations. Obstet Gynecol. 125(5):1236-43, 2015
Slaghekke F et al: Middle cerebral artery peak systolic velocity to predict fetal hemoglobin levels in twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 46(4):432-6, 2015
Van Winden KR et al: Pre-operative twin anemia/polycythemia in the setting of twin-twin transfusion syndrome (TTTS). Fetal Diagn Ther. 37(4):274-80, 2015
Trieu NT et al: Evaluation of the measurement of the middle cerebral artery peak systolic velocity before and after placental laser coagulation in twin-to-twin transfusion syndrome. Prenat Diagn. 32(2):127-30, 2012
Mari G et al: Expected peak velocity of systolic blood flow in the MCA as a function of gestational age. Focus Information Technology. Copyright 2009. Accessed February 9, 2021. http://perinatology.com/calculators/MCA.htm
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KEY FACTS
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TERMINOLOGY
Abbreviations
Twin-anemia polycythemia sequence (TAPS)
Definitions
Monochorionic (MC) twin complication with chronic, slow, unbalanced blood transfusion from donor (D) → recipient (R) twin
Most common after laser therapy for twin-twin transfusion syndrome (TTTS)
May occur spontaneously; develops > 26 weeks in previously uncomplicated MC twins
Spontaneous TAPS can coexist with TTTS
Isolated TAPS much rarer
IMAGING
General Features
Ultrasonographic Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Staging, Grading, & Classification
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Reporting Tips
Selected References
Tollenaar LSA et al: Spontaneous twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 249 cases. Am J Obstet Gynecol. 224(2):213.e1-11, 2021
Wang X et al: Longer distance between umbilical cord insertions is associated with spontaneous twin anemia polycythemia sequence. Acta Obstet Gynecol Scand. 100(2):229-34, 2021
Araújo Pereira J et al: Twin anemia polycythemia sequence. N Engl J Med. 382(6):e9, 2020
Han SJ et al: Short- and long-term outcomes of preterm spontaneous twin anemia-polycythemia sequence. J Perinat Med. ePub, 2020
Khalil A et al: Consensus diagnostic criteria and monitoring of twin anemia-polycythemia sequence: Delphi procedure. Ultrasound Obstet Gynecol. 56(3):388-94, 2020
Liu B et al: Performance of antenatal diagnostic criteria of twin-anemia-polycythemia sequence. J Clin Med. 9(9), 2020
Mao Q et al: Discordant placental oxygenation and autophagy in twin anemia-polycythemia sequence (TAPS). Placenta. 90:9-17, 2020
Shanahan MA et al: Placental anatomy and function in twin gestations. Obstet Gynecol Clin North Am. 47(1):99-116, 2020
Ting YH et al: Outcomes of radiofrequency ablation for selective fetal reduction in complicated monochorionic pregnancies performed before 16 gestational weeks and thereafter. Ultrasound Obstet Gynecol. ePub, 2020
Tollenaar LSA et al: Post-laser twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 164 cases. J Clin Med. 9(6), 2020
Tollenaar LSA et al: High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 55(1):39-46, 2020
Tollenaar LSA et al: Prevalence of placental dichotomy, fetal cardiomegaly and starry-sky liver in twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 56(3):395-9, 2020
Tollenaar LSA et al: Treatment and outcome of 370 cases with spontaneous or post-laser twin anemia-polycythemia sequence managed in 17 fetal therapy centers. Ultrasound Obstet Gynecol. 56(3):378-87, 2020
Visser GL et al: Leukocyte counts and other hematological values in twin-twin transfusion syndrome and twin anemia-polycythemia sequence. Fetal Diagn Ther. 47(2):123-8, 2020
Xu J et al: The utility of MRI for measuring hematocrit in fetal anemia. Am J Obstet Gynecol. 222(1):81.e1-13, 2020
Zhao D et al: Evaluation of color difference in placenta with twin anemia polycythemia sequence. J Vis Exp. 2020
Bahtiyar MO et al: In utero partial exchange transfusion combined with in utero blood transfusion for prenatal management of twin anemia-polycythemia sequence. Fetal Diagn Ther. 45(1):28-35, 2019
Hill KM et al: Intrauterine interventions for the treatment of twin anemia-polycythemia sequence: a systematic review. J Obstet Gynaecol Can. 41(7):981-91, 2019
Jha P et al: US evaluation of twin pregnancies: importance of chorionicity and amnionicity. Radiographics. 39(7):2146-66, 2019
Nicholas LD et al: Twin anemia-polycythemia sequence and routine monitoring practices amongst maternal-fetal medicine specialists in the United States: an initial investigation. J Perinat Med. 47(4):388-92, 2019
Nicholas L et al: Dispelling myths about antenatal TAPS: a call for action for routine MCA-PSV doppler screening in the United States. J Clin Med. 8(7), 2019
Tavares de Sousa M et al: Role of fetal intertwin difference in middle cerebral artery peak systolic velocity in predicting neonatal twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 53(6):794-7, 2019
Tollenaar LSA et al: Improved prediction of twin anemia-polycythemia sequence by delta middle cerebral artery peak systolic velocity: new antenatal classification system. Ultrasound Obstet Gynecol. 53(6):788-93, 2019
Tollenaar LSA et al: Twin-twin transfusion syndrome with anemia-polycythemia: Prevalence, characteristics, and outcome. J Clin Med. 8(8), 2019
Bamberg C et al: Quantified discordant placental echogenicity in twin anemia-polycythemia sequence (TAPS) and middle cerebral artery peak systolic velocity. Ultrasound Obstet Gynecol. 52(3):373-77, 2018
Persico N et al: Fetal Doppler changes 1 week after endoscopic equatorial laser for twin-to-twin transfusion syndrome: a longitudinal study. Prenat Diagn. 38(5):344-48, 2018
De Paepe ME et al: Redness discordance in monochorionic twin placentas: correlation with clinical and placental findings. Placenta. 60:54-60, 2017
Tollenaar LSA et al: Can color difference on the maternal side of the placenta distinguish between acute peripartum twin-twin transfusion syndrome and twin anemia-polycythemia sequence? Placenta. 57:189-93, 2017
Fishel-Bartal M et al: Can middle cerebral artery peak systolic velocity predict polycythemia in monochorionic diamniotic twins? Evidence from a prospective cohort study. Ultrasound Obstet Gynecol. 48(4):470-5, 2016
Guenot C et al: Fetal intra-peritoneal transfusion for the management of very early spontaneous twin anemia-polycythemia sequence in an obese patient with a whole anterior placenta. Twin Res Hum Genet. 19(2):154-7, 2016
Hiersch L et al: Amniotic fluid discordance in monochorionic diamniotic twin pregnancies is associated with increased risk for twin anemia-polycythemia sequence. Prenat Diagn. 36(12):1099-103, 2016
Slaghekke F et al: Antenatal management of twin-twin transfusion syndrome and twin anemia-polycythemia sequence. Expert Rev Hematol. 9(8):815-20, 2016
Stagnati V et al: Inter-twin discrepancy in middle cerebral artery peak systolic velocity and pregnancy outcome in monochorionic diamniotic twin pregnancies. Ultrasound Obstet Gynecol. 48(1):66-71, 2016
Tollenaar LS et al: Twin anemia polycythemia sequence: current views on pathogenesis, diagnostic criteria, perinatal management, and outcome. Twin Res Hum Genet. 19(3):222-33, 2016
Bahtiyar MO et al: The North American Fetal Therapy Network consensus statement: prenatal surveillance of uncomplicated monochorionic gestations. Obstet Gynecol. 125(1):118-23, 2015
Emery SP et al: The North American Fetal Therapy Network Consensus Statement: management of complicated monochorionic gestations. Obstet Gynecol. 126(3):575-84, 2015
Emery SP et al: The North American Fetal Therapy Network Consensus Statement: prenatal management of uncomplicated monochorionic gestations. Obstet Gynecol. 125(5):1236-43, 2015
Slaghekke F et al: Middle cerebral artery peak systolic velocity to predict fetal hemoglobin levels in twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol. 46(4):432-6, 2015
Van Winden KR et al: Pre-operative twin anemia/polycythemia in the setting of twin-twin transfusion syndrome (TTTS). Fetal Diagn Ther. 37(4):274-80, 2015
Trieu NT et al: Evaluation of the measurement of the middle cerebral artery peak systolic velocity before and after placental laser coagulation in twin-to-twin transfusion syndrome. Prenat Diagn. 32(2):127-30, 2012
Mari G et al: Expected peak velocity of systolic blood flow in the MCA as a function of gestational age. Focus Information Technology. Copyright 2009. Accessed February 9, 2021. http://perinatology.com/calculators/MCA.htm
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