From: mcochran@nyx.cs.du.edu (Mark A. Cochran)
Subject: Re: Darcy and viability as important dividing line.
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Date: Fri, 1 Jan 93 04:21:43 GMT

In article <C041BC.GtD@news.cso.uiuc.edu> parker@ehsn17.cen.uiuc.edu (Robert S. Parker) writes:

>"viability" is medically defined (roughly) as the point after which a
>developing fetus could survive outside the womb.  It may also require that
>the fetus could continue to grow "normally" although special care and treatment
>may be needed.  It is generally considered to be sometime around the start of
>the third trimester (I think).  It is not an exact time, it is a general range
>in which it is usually found to occur in those born prematurely.  (They look at
>children born prematurely at various times and compare the development at birth
>to the statistical survival rates to come up with an average figure.)
>
In practice, 26 weeks is considered to be resonably viable.

>Although different studies may find slightly varying results, and medical
>technology may affect it as well, there is no way that an embryo could be
>considered "viable".  I belive it is generally impossible before 24 weeks or
>so (possibly later), but it is certainly "viable" at 8 months and maybe even
>7 months.  For a more precise, "official" figure you would have to ask someone
>more qualified.
>
There have been isolated instances of  survival as early as 22 weeks,
but the gestational age of the infant is always a guesstimate. With
the usage of such interventions as high frequency ventilation, ECMO,
synthetic surfactant, and experience, the survival rates for these
extremly early births is rising. Unfortunately, the chances of them
ever living a normal life is still virtually nill.
In the real world, we *try* to save every wanted pregnancy, from week
20 on. But it just doesn't generally work. Perhaps 1 in 10 will
survive, and at the cost of severe life long problems.
There is no universally accepted definition of viability. In those
states that have laws defining viability, 26 weeks is the date I've
always seen.

>However, "viability" does not vary with the situation.  It is the *earliest*
>time that a prematurely-born child could be "saved" if the best medical care
>is available.  Just because it would probably die if born "at home" but might
>live and grow if born at a hospital does not mean that it would be viable in
>one case and not in the other.  (I suppose you could define "viability" to
>exclude unusual medical care, so that survivability "at home" would be
>important, in which case it would not have been "viable" at the hospital either
>under that definition.)
>
From a strictly pragmatic viewpoint, I'd say tha tthe survival "at
home" definition is more accurate as far as viability goes. With the
uproar over medical costs, it becomes necessary to ask just who is
going to pay the bills?

--
                  Mark Cochran          merlin@eddie.ee.vt.edu
These are the views of my employer. They also represent the views of
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