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Are babies getting bigger? An analysis of birthweight trends in New South Wales, 1990–2005
Author(s) -
Hadfield Ruth M,
Lain Samantha J,
Simpson Judy M,
Ford Jane B,
RaynesGreenow Camille H,
Morris Jonathan M,
Roberts Christine L
Publication year - 2009
Publication title -
medical journal of australia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 131
eISSN - 1326-5377
pISSN - 0025-729X
DOI - 10.5694/j.1326-5377.2009.tb02420.x
Subject(s) - medicine , gestational age , logistic regression , demography , population , gestation , birth weight , obstetrics , pediatrics , pregnancy , environmental health , sociology , genetics , biology
Objective: To determine whether the proportion of babies born large for gestational age (LGA) in New South Wales has increased, and to identify possible reasons for any increase. Design and setting: Population‐based study using data obtained from the NSW Midwives Data Collection, a legislated surveillance system of all births in NSW. Participants: All 1 273 924 live‐born singletons delivered at term (≥ 37 complete weeks’ gestation) in NSW from 1990 to 2005. Main outcome measures: LGA, defined as > 90th centile for sex and gestational age using 1991–1994 Australian centile charts; maternal factors associated with LGA were assessed using logistic regression. Results: The proportion of babies born LGA increased from 9.2% to 10.8% (18% increase) for male infants and from 9.1% to 11.0% (21% increase) for female infants. The mean birthweight increased by 23 g for boys and 25 g for girls over the study period. Increasing maternal age, higher rates of gestational diabetes and a decline in smoking contributed significantly to these increases, but did not fully explain them. Conclusions: There is an increasing trend in the proportion of babies born LGA, which is only partly attributable to decreasing maternal smoking, increasing maternal age and increasing gestational diabetes.