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Birth weight

Birth weight is considered one of the most important indicators of a newborn’s chances of survival. Low or high birth weights are important public health indicators as they occur with greater prevalence in disadvantaged populations.

A newborn is small for gestational age if weighing 500-2499 grams immediately at birth. A newborn is large for gestational age if weighing 4,500 grams or more immediately upon birth.

In Canada, 6.2% of babies were born small for gestational age and 1.7% of babies were born large for gestational age in 2012. The proportion of babies born average weight was 92.2% in 20121

Small for gestational age (SGA)

Babies that are born small for gestational age (SGA) are singleton births that have a weight below the 10th percentile for their gestational age and sex.  An SGA baby weighs less than 90% of babies of the same gestational age and sex in a reference Canadian cohort of singleton births.

Between 2009 and 2014, 367 out of 5,454 singleton live births in the NWHU area were SGA, which equals a proportion of 6.73%.  This is lower and statistically different from the provincial proportion of 9.22% over the same time period

Figure 1:  Small for gestational age (SGA) rates, 2009-2014

small for gestational age 09-14

Source:  Inpatient Discharges 2005-2014, IntelliHEALTH Ontario, Ontario Ministry of Health and Long-Term Care, Date Extracted: January 15, 2016


Figure 2:  Small for gestational age (SGA) rates in the NWHU by municipality, 2009-2014 combined

small for gestational age municipality
Source:  Inpatient Discharges 2005-2014, IntelliHEALTH Ontario, Ontario Ministry of Health and Long-Term Care, Date Extracted: January 15, 2016​

Looking at maternal age groups for SGA births between 2002 and 2011, rates are fairly similar across all ages, ranging from about 4.7% in 15-19 year-olds to 6.3% in 25-29 year-olds (the differences are not statistically significant).

Figure 3:  Small for gestational age (SGA) rates in the NWHU by age group, 2002-2011 combined

small for gestational age by age group
Source: Ontario Vital Statistics Live Birth Data 2002-2011, Ontario Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, Date Extracted: February 24, 2015​

Large for gestational age (LGA)

Babies that are born large for gestational age (LGA) are singletons that weight more than 90% of babies of the same sex and gestational age in the Canadian reference cohort.

Between 2009 and 2014 there were 5,454 singleton live births in the NWHU area, and 867 of them were LGA.  This equals an LGA rate of 15.9% over this time period which is nearly 1 out of 6 live births.  Over the same time period, the LGA rate provincially was 10.3%, which is statistically lower than the rate in the NWHU area.

Source:  Inpatient Discharges 2005-2014, IntelliHEALTH Ontario, Ontario Ministry of Health and Long-Term Care, Date Extracted: January 15, 2016large for gestational age 09-14

Source:  Inpatient Discharges 2005-2014, IntelliHEALTH Ontario, Ontario Ministry of Health and Long-Term Care, Date Extracted: January 15, 2016


Looking at combined LGA rates from 2009 to 2014, Sioux Lookout had the highest rate at 20%, or 1 out of 5 babies that were large for their gestational age.  This rate is statistically higher than the rates in Kenora, Dryden and Fort Frances, and is also statistically higher than the all-municipality combined rate of 14.2% over this time period.  Dryden’s LGA rate of 10.3% is statistically lower the all-municipality rate.


Figure 5:  Large for gestational age (LGA) rates in the NWHU by municipality, 2009-2014 combined​
large for gestational age municipality

Source:  Inpatient Discharges 2005-2014, IntelliHEALTH Ontario, Ontario Ministry of Health and Long-Term Care, Date Extracted: January 15, 2016



 

Between 2002 and 2011 there were slight variations in the LGA rates in different age groups, but there were no statistical differences.​


Figure 6:  Large for gestational age (LGA) rates in the NWHU by age group, 2002-2011 combined​large for gestational age by age group

Source: Ontario Vital Statistics Live Birth Data 2002-2011, Ontario Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, Date Extracted: February 24, 2015


References

1 Statistics Canada. (2016). Live births by birthweight and sex, Canada, provinces and territories. Retrieved from http://www5.statcan.gc.ca/cansim/a21/​