Factors in low birth weight
Online posting: December 17, 1997
Published in print: December 15, 1997 (CMAJ 1998;158:1737)
Re: Recent trends in infant mortality rates and proportions
of low-birth-weight live births in Canada, by K.S. Joseph and
Michael S. Kramer CMAJ 1997;157(5):535-41 [abstract / résumé]
A warning from the cradle? Because they may signal a
deterioration in the nation's health, trends in infant mortality
and low birth weight bear watching, by Graham Chance, Can Med
Assoc J 1997;157(5):549-51 [full text / résumé]
From a study of Canadian data, Drs. Joseph and Kramer report an
increase in low-birth-weight live births in Ontario and suggest
that part of this change may be attributuble to errors caused by
truncation of weights recorded in pounds and ounces. However,
they also note that this explanation does not account for the
increases in each of the birth weight categories when examined by
250-g weight groups.
In his commentary, Dr. Chance rightly points out that the low-
birth-weight live birth rate is a sensitive indicator of
population health, and he calls for more standardized reporting.
To ensure accuracy in reporting I would make a plea for the use
of electronic scales that record birth weight in grams; the
conversion to pounds and ounces, which all parents request,
should be a secondary consideration.
Nonetheless, my experience in high-risk neonatal care in the
Metropolitan Toronto area for over 20 years leads me to believe
that there have been real increases in the incidence of low-
birth-weight live births that have nothing to do with
inaccuracies in reporting but that have major implications for
health care planners and others.
At Women’s College Hospital, one of the tertiary perinatal
facilities for the Central–East Region of Ontario, there has been
a marked change in the demographics of very low-birth-weight
infants (less than 1500 grams at birth). In contrast to a major
database to which we contribute data (the Vermont-Oxford project,
which involves more than 150 neonatal intensive care units
worldwide) we have seen a major shift toward infants from
families of non-European origin. At the same time, the proportion
of infants less than 1500 grams at birth has risen dramatically.
The use of pregnancy induction technology for infertility, which
has been suggested as a cause for at least part of the increase
in low-birth-weight live births, appears to be less of a factor
in this population.
Information from Statistics Canada shows that, whereas before
1961 over 95% of new immigrants to Canada came from European
countries, that proportion was down to 26.5% by the last period
reported (from 1988 through the first 6 months of 1991).[1]
Moreover, according to the most recent immigration data, more
than half of the 208 791 immigrants to Canada in 1995-96 settled
in Ontario,[2] the largest proportion of these in the greater
Metropolitan Toronto area.
Canada has an enviable record throughout the world for its
immigration and refugee policy, a record of which we all should
be proud. However, it would appear that in our health care and
social systems we are not adequately identifying and addressing
the needs of those groups who would most benefit from
interventions described by Chance.
I echo the call of the authors of both articles for more accurate
information but also call on our political decision-makers to
acknowledge that there are identifiable communities at increased
risk, particularly in our urban centres, and to develop
community-based approaches through the current health care
restructuring process in Ontario to address this very real issue.
The benefits to the future health of the mothers and babies of
this province, quite apart from the benefits to the taxpayers,
should be obvious.
Andrew T. Shennan, MB, ChB
Associate Professor
Departments of Paediatrics and of Obstetrics and Gynaecology
University of Toronto
Chief
Department of Newborn and Developmental Paediatrics
Women’s College Hospital
Toronto, Ont.
AShennan@aol.com
References
1. Immigration and citizenship. Statistics Canada: Ottawa;
1992. Cat no. 93-316.
2. CANSIM (Canadian Socio-Economic Information Management
System): matrices 5772–5778 and 6367 to 6279. Ottawa: Statistics
Canada. Available: www.statcan.ca/engli
sh/CANSIM
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