Oral clefts and organic solvent exposure during pregnancy

Abstract

A cumulative case-referent study concerning selected exposures during pregnancy among mothers to children born with oral clefts has been in progress in Finland since December 1, 1977. The present study covering the initial 3.5 years' material can be regarded as a specific, more detailed extension of earlier retrospective studies concerning environmental factors in the causation of oral clefts, using material accumulated from the Finnish Register of Congenital Malformations. Information on exposures was gained by personal interviews with all the mothers. The analysis of different exposures and the classification of the material were performed blindly. Significantly more case-mothers than referent-mothers had been exposed to organic solvents during the first trimester of pregnancy (P less than 0.05).

Maternal occupational risk factors for oral clefts

“…One study found prenatal exposure to lead to be associated with minor anomalies (42). Maternal occupational exposure to solvents (which may include trichloroethylene and glycol ethers) has been related to oral clefts (20)(21)(22). Moreover, solvents have been indirectly incriminated by studies that have found an excess risk of orofacial clefts among leather workers (43,44).…”

“…For oral clefts, the occupations include those in the agricultural (18,19) and health care fields (13). Maternal exposure to solvents has also been associated with clefts (20)(21)(22). Nonetheless, not enough is yet known about the occupational risk factors related to orofacial clefts.…”

Chemical exposure during pregnancy and oral clefts in newborns

“…Referring to solvent use, Holmberg et al (1982) indicated that mothers of cases were more exposed to this heterogeneous group of substances than mothers of controls, especially to aliphatic and aromatic hydrocarbon and their mixtures.…”

Stillbirth and chemical exposure of pregnant workers.

“…The intensity of chemical exposure was expressed as light [less than or equal to one-third of the threshold limit value (TLV) (17)], moderate (more than one-third of the TLV but less than the TLV), and high (equal to or more than the TLV). This classification, based on the assumption that exposure to at least one-third of the TLV may have important biological consequences for the development of the fetus, has been proposed by Holmberg et al (18). It was then used by Eskenazi et al (19) and has recently been refined by McDonald et al (20).…”