Releases Saturday 18 November 2000
No 7271 Volume 321
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(1) WOMEN'S FERTILE DAYS ARE HIGHLY
UNPREDICTABLE
(2) SOCIAL
CLASS DIFFERENCE EXISTS IN
CORONARY HEART
DISEASE
(3) SHORT
AND LONG GAPS BETWEEN PREGNANCIES
CAN HARM WOMEN
(4) A&E
DEPARTMENTS COULD HELP RESOLVE THE
NATIONAL SHORTAGE
OF CORNEAL DONORS
(5) DIFFERENT
PATIENTS NEED DIFFERENT NEEDLE
SIZES
(1) WOMEN'S FERTILE
DAYS ARE HIGHLY
UNPREDICTABLE
(The timing of the "fertile window"
in the menstrual cycle: day
specific estimates from a prospective
study)
http://bmj.com/cgi/content/full/321/7271/1259
A woman's "fertile window" � six days during
her menstrual
cycle when intercourse can result in pregnancy
� is strikingly
unpredictable in any given cycle, according
to a study in this
week's BMJ. The usual clinical guidelines
for getting pregnant
or avoiding pregnancy do not take this
natural variability into
account.
Wilcox and colleagues analysed the menstrual
cycles of 213
healthy women who were planning a pregnancy.
They found
that only 30% of women had their fertile
window entirely
within the days usually identified by
clinical guidelines � that is,
between days 10 and 17 of the menstrual
cycle. On average,
at least 10% of women with regular cycles
were in their fertile
window on any given day between days 6
and 21. Even on
the day their next period was expected,
women had a 1-6%
probability of being fertile, they add.
The timing of the fertile window is even
less predictable for
women with less regular cycles, such as
adolescents, stress
the authors. Women should be aware that
no calendar
method for identifying fertile days is
completely effective, they
conclude.
Contact:
Allen Wilcox, National Institute of Environmental
Health
Sciences, Durham, USA
Email: wilcox{at}niehs.nih.gov
(2) SOCIAL CLASS
DIFFERENCE EXISTS IN
CORONARY HEART DISEASE
(Cross sectional study of differences
in coronary artery
calcification by socioeconomic status)
http://bmj.com/cgi/content/full/321/7271/1262
A study in this week's BMJ finds an unequivocal
social class
difference in coronary heart disease amongst
men and women
in their 30s. These findings have important
implications for
interventions aimed at reducing inequalities
in heart disease.
Colhoun and colleagues examined the rate
of coronary artery
calcification � an accurate measure of
coronary artery disease
� in 149 men and women aged 30-40 years
in relation to
socioeconomic status. They found that
being in the manual
social class was associated with a significantly
higher rate of
calcification. Accounting for known risk
factors - such as
blood pressure, cholesterol levels, smoking
and physical
activity levels - had very little effect
on these results.
Given these findings, interventions aimed
at reducing
inequalities in heart disease must include
young adults and
possibly children, suggest the authors,
and future studies
should include participants in their 20s
and 30s, they add.
The lack of effect when accounting for
risk factors
emphasises that the biological mechanisms,
through which
social inequalities affect risks for coronary
heart disease, have
yet to be discovered, they conclude.
Contact:
Helen Colhoun, Senior Lecturer, University
College London
Medical School, London, UK
Email: helen{at}public-health.ucl.ac.uk
(3) SHORT AND
LONG GAPS BETWEEN PREGNANCIES
CAN HARM WOMEN
(Maternal morbidity and mortality
associated with
interpregnancy interval: cross sectional
study)
http://bmj.com/cgi/content/full/321/7271/1255
Women with gaps between pregnancies of
less than six
months or longer than 59 months are at
increased risk of
complications during pregnancy, finds
a study in this week's
BMJ. However, as the research was carried
out in
developing countries, these results may
not apply to other
populations.
Researchers for the Pan American Health
Organisation in
Uruguay examined the effects of interpregnancy
intervals for
over 400,000 women in Latin America and
the Caribbean.
They found that, compared with women with
intervals
between pregnancies of 18 to 23 months,
women with short
intervals (less than 6 months) had a 2.5-fold
higher risk of
death, a 70% increased risk of bleeding
during the later
stages of pregnancy and premature rupture
of membranes,
and a 30% increased risk of infection
and anaemia. Women
with long intervals (more than 59 months)
between
pregnancies were more likely to develop
pre-eclampsia and
eclampsia.
Although the reasons for these findings
are unclear, the
authors suggest that short intervals between
pregnancies do
not allow the mother to recover from the
physical stresses
imposed by the previous pregnancy. Conversely,
the
"protective" effect for pre-eclampsia
acquired by a woman
through a previous birth is lost after
a long interval, they add.
Despite some limitations, this study underscores
the
importance of birth spacing to promote
safe motherhood, say
the authors. They stress that, as the
research was carried out
in developing countries, the results may
not apply to other
populations.
Contact:
Agustin Conde-Agudelo, Latin American Centre
for
Perinatology and Human Development, Montevideo,
Uruguay
Email: condeagu{at}uniweb.net.co
(4) A&E DEPARTMENTS
COULD HELP RESOLVE THE
NATIONAL SHORTAGE OF CORNEAL DONORS
(Corneal donation in the accident
and emergency department:
observational study)
http://bmj.com/cgi/content/full/321/7271/1263
Patients pronounced dead in accident and
emergency
departments are potential donors of corneas
(transparent
tissue which protects the eyeball), but
this resource is
underused. A study in this week's BMJ
shows how an active
policy for corneal donation can have a
dramatic effect on the
number of corneas donated, helping to
resolve the national
shortage of donor corneal tissue.
Consent for corneal donation was requested
from the
relatives of all patients pronounced dead
in one accident and
emergency department in Scotland from
April to July 1999.
In addition, a simple questionnaire assessed
relatives'
attitudes towards corneal donation. Of
25 patients, consent
was given for nine pairs of corneas to
be donated - a retrieval
rate of 36% compared to 1% in the previous
year. Of these
nine donors, three carried a donor card.
Of 24 questionnaires
completed, 21 relatives thought it was
appropriate to be
approached about corneal donation and
23 were not
distressed by the request.
Projecting these results for one year,
the authors would
expect to double the number of corneas
donated in the west
of Scotland simply by implementing this
policy in one accident
and emergency department. These findings
may also add to
the political debate surrounding the validity
of donor cards
and the need for an opt out policy, say
the authors.
Contact:
Jason Long, Specialist Registrar in Accident
and Emergency,
Monklands Hospital, Airdrie, Scotland,
UK
Email: jason.long{at}ntlworld.com
(5) DIFFERENT
PATIENTS NEED DIFFERENT NEEDLE
SIZES
(The importance of injecting vaccines
into muscle)
http://bmj.com/cgi/content/full/321/7271/1237
A standard size needle does not guarantee
successful
administration of vaccines in all people,
especially for patients
over a certain weight, according to an
editorial in this week's
BMJ.
Jane Zuckerman, a senior lecturer at the
Academic Centre
for Travel Medicine and Vaccines, Royal
Free and University
College Medical School in London, reports
on a recent study
involving 220 adults receiving vaccinations.
It found that a
standard 5/8 inch (16mm) needle could
not penetrate the
upper arm muscle in 17% of men and nearly
50% of women
because of a wide variation in the thickness
of the fat pad
above this muscle. The study recommended
that for men
weighing 59-118kg and women of 60-90kg
it may be safer
to use a 1 inch (25mm) needle, and women
over 90kg may
need a 1.5 inch (38mm) needle.
It is essential that vaccines reach the
muscle to ensure that the
body's immune response is triggered and
to reduce the
likelihood of an adverse reaction, says
the author. A selection
of needles should be available to allow
healthcare
professionals to select a length and gauge
of needle
appropriate to each patient, she concludes.
Contact:
Jane Zuckerman, Senior Lecturer, Academic
Centre for
Travel Medicine and Vaccines, Royal Free
and University
College Medical School, London, UK
Email: j.zuckerman{at}rfc.ucl.ac.uk
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(http://www.eurekalert.org)
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