We now know what is making O have such low endurance. Yesterday, the blood test results came back showing that it appears as if she has hypothyroidism, which tends to be very common in people with Down syndrome. Although for typical people, hypothyroidism tends to strike in middle age or older, in people with Ds, it is not uncommon for them to acquire it as babies or children. O's TSH was normal in the hospital. Her newborn screening was off, but the recheck before she was released was just fine. We had been noticing some symptoms (cold hands and feet and tiredness) and so had the doctor check her thyroid numbers early. Usually they check it once a year. We will be taking O to see an endocrinologist as soon as they can get us in. Hopefully it is really soon! We will surely try to get the earliest appointment available.
Here is what Peter found last night on the internet when he was doing some research on infant hypothyroidism:
This sounds an awful lot like O:
Sounds like the med will be in pill form which can either be given to them or crushed and administered in a dropper. Our experience with our cats may come in handy :-)