Small for Gestational Age Babies born small for their gestational age (SGA) are singletons weighing less than 90% of babies of the same sex and gestational age in a reference Canadian cohort of singleton births. SGA babies are more likely to become ill and/or die than normal birth weight newborns. SGA babies can also be low birth weight which means they weigh less than 2,500 grams (or 5 lbs 8 oz) at birth. This condition is linked to increased risk of type 2 diabetes and coronary heart disease later in life (1). In industrialized countries, maternal cigarette smoking during pregnancy accounts for 30% to 40% of SGA births; "genetically related factors" such as history of SGA pregnancies, maternal race, short maternal stature and fetal sex account for 20% to 30%; nutritional factors including pre-pregnancy weight, weight gain and low caloric intake for 10% to 15%; and the number of times the mother has given birth and her general state of health for 5% to 10% (1). Between 1986 and 2006 in Simcoe Muskoka, the SGA rate has varied between 9.2% and 16.4% of all singleton live births. During the same time period the percentage of live births that were low birth weight varied between 5% and 6% with the rate for Ontario being less than a percentage higher. These data come from the Vital Statistics database. Large for Gestational Age Babies born large for their gestational age (LGA) are singletons weighing more than 90% of babies of the same sex and gestational age in the same Canadian cohort. When babies are born large for their gestational age they are at higher risk for birth complications including shoulder dystocia, brachial plexus injury and Erb’s palsy. As well, the mother is at higher risk for postpartum hemorrhage. Routine surveillance and ongoing monitoring of pregnancies, especially high-risk pregnancies, help identify fetuses at high risk of being LGA. In Canada, the number of babies born large for their gestational age has increased since 1995 (1). Reasons for this are not entirely clear although ethnicity and the mother’s diet appear to play a role. Maternal diabetes has been established as an important risk factor for LGA. In turn, a baby with a high birth weight may be at increased risk for type 2 diabetes later in life. Between 1986 and 2006 in Simcoe Muskoka the LGA rate has varied between 11.1% and 18.4% of all singleton live births. These data come from the Vital Statistics database. 1. Public Health Agency of Canada, Canadian Perinatal Surveillance Report 2008 |