Socio-economic inequalities in low-birth weight, full-term babies from singleton pregnancies in Taiwan

Summary Objectives This study investigated the chronological trend of low-birth weight in full-term babies (TLBW) in Taiwan in the 1980s and 1990s when the nation experienced a rapid economic advancement, and assessed the association between TLBW and parental education and marital status. Design Data from liveborn singletons from Taiwan's birth registry, born between 1978 and 1997, were used to calculate overall and socio-economic factor-specific rates of TLBW for every 2-year interval in this 20-year period. Methods Logistic regression models were used to assess the trend of TLBW rates, and the interaction between secular time, selected demographic factors and other predictors. Results Among 6,159,070 full-term, liveborn singletons, 208,729 were TLBW. The average annual rate of TLBW was 3.39% in the study period. The period-specific TLBW declined monotonically from 4.41% in 1978–1979 to 2.49% in 1996–1997, representing a 43% deduction. Multiple logistic regression demonstrated persistent declining trends irrespective of the educational level or marital status of the parents. However, the decline was slower for populations of lower socio-economic status, such as less-educated parents and unmarried mothers, which enhanced the inequalities of TLBW risk across populations. The TLBW risk ratios of the least-educated mothers to the most-educated mothers increased from 1.43 in 1978–1979 to 2.05 in 1996–1997. Unmarried status was an independent predictor of elevated risk of TLBW. Conclusions The association between socio-economic inequality and the risk of TLBW infants was sustained over the 1980s and 1990s in Taiwan. Interventions are necessary to promote antenatal care and educational attainment, particularly for lower socio-economic and socially deprived populations in Taiwan.