From: utzoo!decvax!microsof!uw-beave!ubc-visi!ubc-medg!naomi
Newsgroups: net.med
Title: VDTs and Pregnancy - again - (nf)
Article-I.D.: ubc-medg.118
Posted: Tue Mar 15 14:05:48 1983
Received: Tue Mar 22 23:33:51 1983

#N:ubc-medgen:5500001:000:2614
ubc-medgen!naomi    Mar 15 10:32:00 1983

I know we've been through this before, but I'd like to keep the discussion
of VDT safety going.  

As you may have heard, there was an outbreak of miscarriages among VDT
operators in Surrey Memorial Hospital, near Vancouver.  Needless to say, our
secretarial staff feel nervous about the safety of our terminals (which
apparently do not have PCBs.)  This is the second such outbreak I know of
in Canada, but I still have not seen the results of the investigations of 
these incidents.  

I have heard over and over that the main work hazards are eye-strain, etc.
However, I don't believe that these were follow-ups of miscarriage cases.
Has anyone out there heard any results from any follow-up studies?

Another thing that is puzzling, is that there are a lot of female programmers
and I haven't heard too many reports of pregnancy problems among them.  Of
course, there are a lot more women who use word-processors, or data entry
equipment.  Does anyone know of any reports that
suggest an abnormal incidence of miscarriages among women programmers?

Statistics on miscarriage rates are surprisingly hard to come by.
Miscarriage in the first few weeks is often unreported and possibly not
known even to the mother.  I work in a department that uses this type of
information, but the best we could find was 10-40% spontaneous abortion in
the first 20 weeks (after that it is a "stillbirth".) The stillbirths add
another 5-10%.  Women over 30 are at the high end of this scale.
In short, a very high percentage of pregnancies do not come
to term.  So, in a group of 5-10 pregnant women, there is a quite high
probability of 3 or more miscarriages, without appealing to common causes -
even psychosomatic ones.  By comparison, breast cancer is much rarer than
miscarriage, but I was told of a work situation in which 5 of 12 women were
diagnosed with breast cancer in a 6 month period.

Statistics is a wonderful field.  When I started this article, yesterday, I
made a list of all the women I know who have been pregnant and came up 
with a somewhat higher miscarriage rate for the VDT users.  However, most of
these women were in their 30s, compared to the nonusers, who were in their 
20s. Now that I see the statistics, fuzzy though they are, I feel very 
reassured, and have come to believe that these "outbreaks" of miscarriages 
can be explained as statistical phenomenon. (Randomness implies clustering!)

               not afraid to be a biostatistician and use a VDT
               but a bit scared of being over thirty
               Naomi Altman
!decvax!microsoft!uw-beaver!ubc-vision!ubc-medgen!naomi