Raising Awareness for TAPS, A Rare Pregnancy Complication with Twins


At first, everything in Amberlyn Smith’s pregnancy seemed to be going smoothly. When she was just over 29 weeks pregnant, her screening tests appeared to be normal. However, at just shy of 32 weeks pregnant, something changed. According to a news release from the University of Texas Health Science Center at Houston, Amberlyn got some potentially concerning news when she went for her ultrasound: there were changes in size and blood flow between her babies. But what did that mean? Well, Amberlyn was given a diagnosis of twin anemia polycythemia sequence (TAPS), a rare pregnancy complication that can occur with monochorionic twins.

Amberlyn’s Story

After Amberlyn visited her doctor, he told her that she must be hospitalized and monitored. In cases of TAPS, Dr. Ramesha Papanna, MD, MPH explains that the blood imbalance between the twins can sometimes normalize. However, in other cases, it could worsen. Luckily, when the twins’ conditions did worsen, Amberlyn was already being watched. Dr. Papanna made the decision to deliver the twins early, and her sons were born on Christmas Eve. After, newborns Hudson and Steven were placed into the neonatal intensive care unit (NICU).

TAPS can be diagnosed using Doppler technology, which identifies how blood flows through the middle cerebral artery (MCA). Dr. Alexandria Hill, MD, states that those who are pregnant with twins should have MCA monitoring every 2 weeks starting at week 16. This is to be able to identify any complications early, before later stages of the pregnancy when it cannot be treated. However, the current MCA screening practices are not standardized. Dr. Hill argues that the standardization of these practices can better assist those across the country (and globally), and should be required.

So how are Steven and Hudson doing now? Well, thanks to the early detection, I am happy to report that Amberlyn’s babies are doing just fine!

Twin Anemia Polycythemia Sequence (TAPS)

According to Johns Hopkins Medicine, twin anemia polycythemia sequence (TAPS) is:

a rare condition that occurs when there are unequal blood counts between the twins in the womb. Unequal blood counts cause the twins to suffer from an imbalance in red blood cells and hemoglobin, [meaning that] one twin is not receiving the appropriate amount of oxygen and nutrients it needs to develop properly.

TAPS occurs in up to 5-10% of monochorionic twin pregnancies, which means the twins share a placenta. The twins in this case are known as the donor twin (the one losing blood) or the recipient twin (the one receiving blood). Ultimately, doctors do not know the cause of TAPS. Some believe it occurs spontaneously, while others believe it could arise following surgery for twin-to-twin transfusion syndrome (TTTS).

For diagnosis, doctors must be able to see:

  • Slower than average blood flow in the recipient twin
  • Polycythemia (increased red blood cell level, which may cause slow, thick blood) in the recipient twin
  • Fast than average blood flow in the donor twin
  • Anemia (low red blood cell count) in the donor twin

Because of the inherent health issues, the donor twin is at risk of death. If the condition is not caught and treated early enough, TAPS is fatal for one twin in around 10% of all cases. TAPS can be identified early by maternal-fetal medicine physicians or practices. In cases where treatment is needed, the mother may need to undergo fetal surgical interventions.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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