Original ArticlesWhy are babies getting bigger? Temporal trends in fetal growth and its determinants☆,☆☆,★
Section snippets
Methods
We designed a hospital-based historical cohort study at the Royal Victoria Hospital, a McGill University teaching hospital with a clinically detailed computerized obstetric and neonatal database that has been maintained since January 1, 1978.12 This study is based on 61,437 inborn, nonmalformed singleton live births of 22 to 43 weeks' gestational age without antenatal transfer, who were delivered between January 1, 1978 and March 31, 1996. We excluded both antenatal transfers and outborn
Results
Table I shows the trends in mean birth weight, mean birth weight-for-gestational-age Z score, and SGA and LGA proportions in singleton live births ≥37 completed weeks.Period n Mean Birth weight (g) MeanZ score % SGA % LGA 1978-79 5626 3419 −0.091 11.1 8.0 1980-81 5659 3426 −0.046 10.3 8.4 1982-83 6333 3453 0.013 8.9 9.9 1984-85 6222 3449 0.050 8.2 10.0 1986-87 6192 3465 0.102 7.8 11.2 1988-89
Discussion
The observed temporal trends in mean birth weight, mean birth weight-for-gestational age Z score, SGA, and LGA proportions all indicate an increase in fetal growth between 1978 and 1996 at this tertiary-care Montreal teaching hospital. As hypothesized, the increase was restricted to births ≥37 weeks (except for an inexplicable rise in LGA birth among infants ≤33 weeks), and the increase was largely the result of a rise in prepregnancy BMI, gestational weight gain, and gestational diabetes and
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Cited by (0)
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Drs Kramer, Platt, Joseph, and Wen are recipients of career investigator awards from the Canadian Institutes of Health Research.
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Dr Joseph is also a Clinical Scholar of the Dalhousie University Faculty of Medicine.
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Reprint requests: Michael S. Kramer, MD, 2300 Tupper St, Montréal, Québec, Canada H3H 1P3.