Trend of congenital anomalies over 20 years ascertained by population-based monitoring in Ishikawa Prefecture, Japan.

Monitoring in Ishikawa Prefecture (mean population; 1,150,000), during the 20-year period from 1981 to 2000, involved monitoring the prevalence of congenital anomalies starting at gestational week 22. The main objectives of the present study were (1) to investigate the trend over the past 20 years in the prevalence of congenital anomalies, and (2) to investigate whether there is area accumulation in congenital anomalies or not. In addition, the prevalence of well-known risk factors such as smoking, drinking and family history among cases with congenital anomalies was analyzed to obtain clues to the background of such anomalies. During the 20 years, more than 200,000 births have been observed. Thirty-three selected congenital anomalies, consisting mainly of external anomalies, were analyzed in this study. The percentage of children born with congenital anomalies did not change markedly between the first and second halves of the monitoring period, remaining at approximately 4.5/1,000 births. There was also no significant change in annual trends in either Ishikawa Prefecture as a whole or in the three regions within Ishikawa. The prevalence of congenital anomalies by type showed a significant decrease in anencephaly and spina bifida. In contrast, Down syndrome and microcephaly increased significantly. The mean maternal age for Down syndrome increased significantly from the first-half period to the second-half period. The percentage of children with polydactyly whose mother smoked were relatively higher than that for the other congenital anomalies.

Effects of maternal dioxin exposure on newborn size at birth among Japanese mother-infant pairs.

OBJECTIVE: Maternal exposure to dioxins [polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (DFs)] during pregnancy is known to affect infant growth and neurodevelopment in humans and animals. The aim of this study was to investigate the relationship between newborn size and the concentration of dioxin isomers in breast milk and to subsequently evaluate the potential toxicity of each dioxin isomer among mothers living in sea coast areas who are at a high risk of contamination due to a high consumption of fish. METHODS: A total of 75 milk samples were obtained within 1 month of delivery from Japanese mothers living in the coastal areas of the Japan Sea. The relationships between the levels of seven dioxins and ten furan isomers in maternal breast milk, measured by high-resolution-gas chromatography/mass spectrometry, and the birth size of newborns, which is related to fetal growth, were investigated after adjustment for confounding factors. RESULTS: The concentrations of 1,2,3,6,7,8-HxCDD (hexachlorodibenzo-p-dioxin), 2,3,4,7,8-PeCDF (pentachlorodibenzofuran), 2,3,4,6,7,8-HxCDF, and three dioxin toxic equivalent (TEQ) levels (PCDDs-TEQ, PCDFs-TEQ, and total-TEQ) in maternal breast milk were inversely correlated to newborn length even after adjustment for gestational weeks, infant sex, and maternal age and height. These isomers were abundant among the 17 isomers tested and reflected the TEQ levels. Only 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), the most toxic isomer, was negatively correlated with newborn head circumference, even after adjustment for gestational weeks, infant birth weight, and other confounding factors. CONCLUSIONS: Based on our results, fetal growth may be influenced by maternal total exposure to dioxins, but only exposure to 2,3,7,8-TCDD would appear to possibly affect fetal head size during pregnancy.