From: xtkmg@trentu.ca (Kate Gregory)
Subject: Re: What's an NST?
Summary: Failing means nothing; passing is good. Fun test.
Keywords: test done in pregnancy
Organization: Trent University, Ontario
Distribution: usa
Date: Fri, 16 Oct 1992 18:07:50 GMT


I had 24 NSTs in 23 days while in the hospital for toxemia. Women
who go post term often have them every other day. Time was you got
induced by the calendar: you could go 11 or 14 or 17 days past
date and then you'd be induced, or sectioned if that failed. Then
a doctor in Toronto (plug plug) started something called "The
Toronto Post Term Study" which has been going on for years and showed
that some women can go much much longer and have healthy babies,
skipping the risks of induction or section, while others can't even
go to 11 days PT. I had a friend in this study: her boy is almost
seven now and the study is still going on. Among other things
it showed prostaglandin gel is good to prepare the cervix
for pitocin induction: before the study we couldn't have the gel
in Canada.

Anyway, it's a simple test. It was the highlight of my day (and
one day I had two). You put on a belt pressure monitor which
measures your Braxton Hick's contractions. (Incidentally if
they give you pitocin to make real contractions, this is a Stress
Test) and a fetal heartrate monitor too. They both print out
on the same piece of paper. On the old machines they hand you a
pen and ask you to write on the strip if the baby moves: on the
new ones they give you a remote thing like a Jeopardy contestant
for you to signal movements. 

Then they have you lie around and record some number of contractions
and some number of movements. If the baby doesn't happen to be
moving at the moment, they do one of the following
  - say it doesn't count if they make her move, and tell
    you to come back this afternoon
  - say it's OK if she moves because you shift position but
    everything else is bogus, and make you roll over etc
  - say it's OK if she moves because she hears stuff but
    everything else is bogus, and turn the radio on
  - say it's OK if she moves no matter what, and do all
    of the above plus give you orange juice or have
    you talk to the baby and ask for movement.

It takes ten minutes some days, half hour others. The whole
time you can hear the heartbeat. The tech is usually happy
to give you a piece of the strip: I have one showing a classic
BH contraction and a movement. A fair amount of the time
the baby moves away from the heartrate thing and it drops
to zero or they get yours (about half the rate) and you
help the tech. chase the baby around. Very funny and reminds
you the monitors are sometimes wrong so you won't panic if
they "lose" the heartrate while they monitor you in labour.

It's important to remember that "failing" a NonStressTest doesn't
mean the baby is in any danger whatsoever. None. The only meaningful
result from an NST is a pass. Such babies are OK for another day or
two (depending on the reason for the test) and there's nothing
to worry about. Babies who "fail" may be OK or they may not.
They are not in fetal distress. You are just no longer 100% sure
they are fine. That's why they only *induce* after failed NSTs.
And only if they're already pretty sure the baby is big enough
that being born now rather than a week from now is not an issue.

Let me rephrase this more strongly, and I'm quoting my doctor:
"if you pass the test we know that baby is fine and will be
fine at least two more days. If you fail the test we know
nothing. It's as though we forgot to do it today. There is
no information provided by a failed test." I know that doesn't
make much sense , but it has to do with the outcomes of
previous labours. Whenever there had been a passed NST in the
previous few days, the labours went well; those with a failed
NST or no recent NST went about the same as each other; sometimes
well and sometimes not so well. They also found that days-past-dates
meant almost nothing as well. A failed NST does not
mean something is wrong.

I liked my NSTs. And for postterm women, those tests are what are
giving you the chance to go into labour on your own.

Kate