An ethical examination of twin anemia polycythemia sequence screening


In a recent US case study, researchers have shed light on the ethical challenges surrounding diagnosing and managing Twin Anemia Polycythemia Sequence (TAPS), a rare condition affecting monochorionic twin pregnancies. The study highlights the importance of veracity, respect for persons, justice, and disability rights in providing comprehensive care for families affected by TAPS.

is a rare and often fatal disease that affects monochorionic twins. It is characterised by an unwanted small surface connection in the placenta (when there should not be one), which causes a transfer of red blood cells from “donor” twin to “recipient” twin. This leads to anaemia (deficiency of red blood cells or of haemoglobin) in one twin and polycythemia (excess of red blood cells) in the other. TAPS can also lead to a higher risk of preterm birth and other health complications. It is difficult to diagnose, as it does not present with notorious fluid imbalances or other physical symptoms. However, the impact of a TAPS diagnosis on families remains largely unknown. In contrast, related placental diseases like Twin-to-Twin Transfusion Syndrome (TTTS) have been extensively studied, revealing the risk of post-traumatic stress disorder, depression, and anxiety among mothers. Research suggests that improving TAPS screening guidelines can help prepare parents much earlier about associated risks, treatments, and required follow-up care throughout a child’s development.

A case study from the US aimed to promote awareness among healthcare professionals, families, and others impacted by TAPS by illustrating the clinical and ethical challenges of TAPS screening and care with the help of a case example. The example was based on a parent’s experience living with TAPS.

The case started with a healthy female patient who was pregnant with monochorionic-diamniotic (MCDA) twins. Guidelines for twin pregnancy were followed, including a 21-gestational-week check in which the doctor reported a recognisable size difference between the twins. Because of no further alarming findings, additional tests were not performed. At another routine appointment at 32 gestational weeks, both twins presented health complications, and an urgent delivery was successfully conducted. Twin A was born with polycythemia, while Twin B was born anaemic, conditions that aligned with TTTS. They were stabilised, and finally, once the TTTS-diagnosed twins passed all other newborn screenings, they were discharged. Only the placental pathology was unusual.

During follow-up care, twin B showed developmental difficulties, especially in speech. Twin B’s speech, cognition, and motor skills remained significantly delayed, revealing deafness and the additional need for supportive occupational and physical therapy. At that point, the family had voiced feeling overwhelmed and powerless and a wish to revise the initial TTTS diagnosis. This situation led to a new correct diagnosis of TAPS.

Researchers believe that if the mother had received prenatal TAPS screening during pregnancy, she and her twins would have had fewer burdens and earlier support. Due to the lack of guidelines regarding TAPS screening, healthcare professionals do not have the necessary information to provide optimal care.

As part of the analyses, researchers provided some general recommendations for ethical challenges associated with TAPS, including the principles of veracity, respect for persons, justice, and disability rights. They defined these principles as follows:

  • Veracity emphasises the importance of honest and transparent communication between healthcare professionals and patients. In the case of TAPS, the lack of information and delayed diagnosis hindered parents’ ability to make informed decisions. Physicians should also strive to disclose the latest research to patients.
  • Respect for persons and autonomy is crucial for enabling parents to make autonomous decisions. Healthcare providers should consider screening and treatment options, as well as the long-term outcomes of TAPS, to empower patients in shared decision-making. Revised TAPS guidelines are also essential.
  • The principle of justice calls for equitable distribution of screening, counselling, and developmental care opportunities for families affected by TAPS. While acknowledging the financial burdens associated with additional screening and testing, denying access to beneficial options is unjust. It is essential to develop solutions that reduce immediate financial burdens while preventing long-term costs.
  • Disability rights and the provision of comprehensive care for children diagnosed with TAPS are vital for improving their quality of life. Coordination of Infant- and family-centred developmental care can help parents navigate the challenges of raising a child with a disability. Ensuring access to early learning and educational opportunities is a health-based right for children. Healthcare professionals must address health disparities and reduce bias in care.

Furthermore, the study emphasises the need for international registries and collaboration to gather data and advance research in this field. Revisions in screening guidelines to improve patient care are also important. By incorporating researchers’ recommendations, healthcare professionals can provide comprehensive care and support to families affected by TAPS.


Paper available at: Ethics, Medicine and Public Health / Science Direct

Full list of authors: J.M. Aultman, S. Ernst, R. Fischbein, L. Nicholas


Find out more about TAPS from “The TAPS Support Foundation