Socio-economic correlates of adverse pregnancy outcomes in Hong Kong: an analysis using individual vital registration records

Birth weight below 2500 gr significantly increases chances of infant death and morbidity in childhood and adulthood. Birth weight above 4500 grams has been linked to perinatal complications and ill health later on. Identification of mediators is crucial in reducing infant mortality and health care expenditure. The present study examines associations of socio-demographic factors and immigrant status of the parents with adverse pregnancy outcomes, using multinomial regression modelling of 828,975 births of singletons occurring in Hong Kong over 1995-2009. The analysis considers VLBW (<1500 gr), LBW ( 1500 gr & <2500) and HBW births ( 4500 grams) in comparison to births of normal weight ( 2500 gr & <4500).
The findings indicate the expected significant adverse associations between female gender, primiparity and teenage and advanced age of the mother with compromised birth outcomes. A strong socio-economic gradient is apparent, more marked among LBW births. Regarding immigrant status, women born in South and South-East Asia exhibit consistently higher odds of a compromised outcome. Women born in Hong Kong have significantly higher chances of LBW births while Mainland Chinese and parents from developed countries face higher odds of HBW births. The study identifies vulnerable groups of population in need of support.