Low birth weight in China and Finland.

Although a developing country, China has a lower occurrence of low birth weight (LBW) than many developed countries. This study of two population-based one-year birth cohorts, from Finland in 1985-86 and China in 1992, shows the occurrence of low birth weight (LBW) (1000- < 2500 g) among singletons to be 2.6 percent in the Chinese cohort and 3.0 percent in the Finnish one, and that of preterm births (28- < 37 weeks) 2.7 percent and 4.5 percent, respectively. The main component of LBW is term LBW (57.4 percent) in the Chinese case and preterm LBW (64.7 percent) in the Finnish case. The perinatal mortality rate (PMR) was twice as high in the Chinese cohort (13.0 vs. 5.9 per thousand). The occurrence of LBW in the Finnish cohort decreased to 2.3 percent after crosstabulation of the Finnish mothers to conform in structure to the population of Chinese mothers in terms of maternal age, marital status and maternal smoking. The result suggests that the lower incidence of LBW in the Chinese cohort seems to be a reflection of the Chinese socio-cultural environment, which provides Chinese mothers with favourable characteristics. The Finnish excess LBW would have disappeared if the mothers had possessed those characteristics as well. The excess perinatal deaths in the Chinese series might be explained by the different levels of perinatal health care in the two countries.