We say about 1:200 on (top of background risk) and our experience fits that
reasonably well.
I was however at a recent seminar where a leading radiologist advocated
giving a figure of 1% (1:100).
It would seem probable that the pregnancy loss rate is going to be operator
and population specific to some degree. Should we then quote "across the
board" figures, or should we tell our patients: "in our experience, 1out of
x100 pregnancies will be lost because of the procedure".
--
Martin Necas.
-----Original Message-----
From: ultrasound@obgyn.net [mailto:ultrasound@obgyn.net] On Behalf Of
Allen Worrall
Sent: Saturday, 19 May 2001 12:33 p.m.
To: Multiple recipients of list ULTRASOUND
Subject: Risk of 2nd trimester amniocentesis
When talking to patients, what risk of 2nd trimester amniocentesis do
you mention? I think the usual is 1/200 to 1/300, although it is not
clear to me if that is the risk of fetal loss, or just the risk of
"something" happening.
Amniocentesis was just coming into practice when I stopped doing OB,
about 26 years ago, so I have little personal experience, but I have
provided the ultrasound quidance for many. I have come to wonder,
however, if the risk mentioned above really is valid today. Is it
possible that the above risk is from the pre-ultrasound experience? My
observations of my colleagues' practices and techniques suggests that
the risk of 2nd trimester amniocentesis is much lower than 1/200 to
1/300.
Is it true that age 35 to offer amniocentesis to detect Down came about
because that was the point at which the risk of the amniocentesis
equaled the risk of having a baby with Down? If so, and if we determined
that the risk of amniocentesis today is much lower than we think, what
impact should this have on the way we counsel patients in this area?
I recently heard from a patient (not in my community) who had an
increased nuchal translucency (I do not remember what it was), a 2nd
trimester triple screen risk of Down of 1/76, and opted not to have a
2nd trimester amniocentesis, because she was afraid of the
amniocentesis. The outcome of this pregnancy is not yet known.
At the AIUM meeting 2 months ago I heard an anecdotal story of a
resident, or maybe it was the wife of a resident, who died of sepsis
from an amniocentesis!
So are we correct to continue to counsel that the risk of something bad
happening from amniocentesis is 1/200 to 1/300?
Are there any who have kept track of how many amniocenteses they have
done, and how many problems there have been? I recently talked with a
young doctor who said he has done probably 1000 and is unaware of any
problems. Are there other doctors whose personal experience would lead
them to think 1/200 to 1/300 is too high?
--
Joseph A Worrall MD RDMS
Fairbanks, Alaska
