Very Low, Low and Heavy Weight Births in Hong Kong Sar: How Important Is Socioeconomic and Migrant Status?

Abstract

Identification of modifiable factors and mediators linked to low and heavy birth weight is crucial in reducing infant mortality and health care expenditure. The present paper explores the associations of socio-demographic factors and immigrant status of parents with adverse pregnancy outcomes in Hong Kong. The analysis compares very low birth weight (VLBW: <1500 g), low birth weight (LBW: ≥ 1500 g and <2500 g) and heavy birth weight births (HBW: ≥ 4500 g) with births of normal weight (≥ 2500 g and <4500 g) using multinomial regression modelling of a large dataset of 828,975 births of singletons occurring between 1995 and 2009. The findings indicate the expected significant adverse associations between teenage and advanced age of the mother with compromised birth outcomes; teenage motherhood, however, has a protective effect against HBW births. A strong socioeconomic gradient is apparent, more marked among LBW births; low educational attainment of the father, low occupational class, public housing and single motherhood are strongly related to adverse pregnancy outcomes. 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 high-risk groups such as teenage, older and single mothers, South-East Asians and couples of low socioeconomic profile. Implementation of policies supporting these groups would be beneficial.

Socioeconomic disparities in preterm birth and birth weight in a non-Western developed setting: evidence from Hong Kong's ‘Children of 1997’ birth cohort

“…Nevertheless, residing in private housing was associated with higher birth weight for gestational age, although this association was not robust to adjustment for mother's age. This is consistent with two cross-sectional studies in Hong Kong, showing a higher prevalence of LBW among mothers who resided in public compared with private housing adjusted for parity,20 and lower birth weight among mothers who resided in temporary compared with private housing adjusting for parity 21. However, neither study adjusted for gestational age 20 21.…”

“…This is consistent with two cross-sectional studies in Hong Kong, showing a higher prevalence of LBW among mothers who resided in public compared with private housing adjusted for parity,20 and lower birth weight among mothers who resided in temporary compared with private housing adjusting for parity 21. However, neither study adjusted for gestational age 20 21. Studies elsewhere have not evaluated type of housing per se,7 although homelessness during pregnancy has been associated with PTB and LBW 32…”

“…Women in Hong Kong have relatively low rates of smoking (5%) or heavy alcohol use (4%),18 19 which could be intermediate risk factors for the associations of SEP with PTB, birth weight and SGA 9. Cross-sectional studies in Hong Kong have shown lower parental SEP to be associated with higher prevalence of LBW,20 and lower birth weight after adjusting for parity 21. However, neither study accounted for gestational age, which is a major determinant of birth weight 4.…”

‘Maternity migration’ and the increased sex ratio at birth in Hong Kong SAR

“…Within the past decade, the number of Chinese Mainlanders giving birth in Hong Kong has risen dramatically (Leung 2011;HKCSD 2012;Verropoulou and Basten 2013). This migration for birth is a clear driver behind the skewed SRB in the SAR.…”

“…Hong Kong's TSR is markedly different from that of Mainland China (TSR 108.0) and other East Asian developed territories such as Republic of Korea (TSR 99.4) and Taiwan (TSR 102.4) (UNPD 2011). However, these figures mask an important feature*namely, a significant rise in the SRB in the SAR over the past decade (Wong et al 2010;Leung 2011;Verropoulou and Basten 2013).…”