Risk of congenital anomalies in relation to the uptake of trihalomethane from drinking water during pregnancy
Objectives Congenital anomalies have been inconsistently associated with maternal crude estimated exposure to drinking water trihalomethane (THM). We investigated the relationship between individual THM uptake during the first trimester of pregnancy and congenital anomalies.
Methods We estimated maternal THM uptake for 3074 live births using residential tap water concentrations, drinking water ingestion, showering and bathing, and uptake factors of THM in the blood. Multiple logistic regression was used to investigate the association of THM exposure with congenital anomalies.
Results We observed no statistically significant relationships between congenital anomalies and the total THM internal dose. We found little indication of a dose-response relationship for brominated THM and congenital heart anomalies. The relationship was statistically significant for bromodichloromethane (BDCM) (OR=2.16, 95% CI 1.05 to 4.46, highest vs lowest tertile) during the first month of pregnancy. During the first trimester of pregnancy, the probability of developing heart anomalies increased for every 0.1 μg/d increase in the BDCM and for every 0.01 μg/d increase in the internal dibromochloromethane (DBCM) dose (OR 1.70, 95% CI 1.09 to 2.66, and OR 1.25, 95% CI 1.01 to 1.54, respectively). A dose-response relationship was evident for musculoskeletal anomalies and DBCM exposure during the first and second months of pregnancy, while BDCM exposure tended to increase the risk of urogenital anomalies.
Conclusions This study shows some evidence for an association between the internal dose of THM and the risk of congenital anomalies. In particular, increased prenatal exposure to brominated THM might increase the risk of congenital heart and musculoskeletal anomalies.
In questo studio di coorte, effettuato su donne in stato di gravidanza e basato su dettagliate analisi del consumo individuale di acqua, sono emerse prove statisticamente significative che l'esposizione materna a trialometani bromurati, derivati dai processi di clorazione dell’acqua potabile, aumentano il rischio di cardiopatie congenite e anomalie muscolo scheletriche fetali, indipendentemente da altri fattori di confondimento materni.
I risultati di questa ricerca, come di altre recenti sul tema, sono ancora da approfondire, ma si sta sviluppando un crescente interesse sull’argomento.