Socioeconomic and maternal determinants of small-for-gestational age births: patterns of increasing disparity.
OBJECTIVE
To better characterize the relation between socioeconomic disadvantage and small-for-gestational age births (SGA).


METHODS
Analysis of data from a mandatory population-based surveillance system.


METHODS
Public or private hospitals and at home.


METHODS
All 877,951 singleton births occurring in New South Wales, Australia, between 1994 and 2004.


METHODS
Multilevel models were developed to determine the factors associated with babies weighing less than the 3rd percentile for gestation and gender.


METHODS
Odds of SGA.


RESULTS
The risk of SGA increased with increasing socioeconomic disadvantage. Smoking accounted for approximately 40% of the increased risk associated with socioeconomic disadvantage, and delayed antenatal care approximately 5%. While the absolute rate of SGA remained stable over the study period, the odds of SGA in mothers living in the most disadvantaged areas compared to those in the least disadvantaged areas increased from approximately 1.7 to 2.2. This trend persisted after accounting for maternal smoking. The risk of SGA over this period also increased in mothers commencing antenatal care after the first trimester. After accounting for smoking, socioeconomic disadvantage and clinical conditions, mothers under 21 years of age were at reduced risk of SGA, but mothers over 35 were at increased risk.


CONCLUSIONS
Socioeconomic disadvantage remains one of the dominant determinants of SGA, even in a developed country with universal insurance. This relation appears to be strengthening. Smoking patterns, inadequate antenatal care and clinical conditions partially account for this association and trend, however, most is mediated by other factors.
Beard
John R
JR
New York Academy of Medicine, Center for Urban Epidemiologic Studies, New York, NY 10029, USA. jbeard@nyam.org
Lincoln
Doug
D
Donoghue
Deborah
D
Taylor
Danielle
D
Summerhayes
Richard
R
Dunn
Therese M
TM
Earnest
Arul
A
Morgan
Geoff
G