Handbook of Solvents - George Wypych - ChemTech - Ventech!

20.3 Pregnancy outcome following solvent exposure 1353
vious hexane levels reported in the literature, IOL hexane exposure levels are substantially
lower.
In mice levels of inhalation exposure to toluene have included 100 to 2,000 ppm at
various times during gestation as well as at various durations of exposure (6-24
hours/day). 41 Growth and skeletal retardation were noted at lower levels (133 ppm and 266
ppm, respectively) when such exposures were of a 12-24 hour duration for at least half of
the gestation period. 41 Human levels of inhaled toluene exposure that would be comparable
would be those obtained by chronic abusers (5,000-12,000 ppm). The only noted malformations
were an increase in the frequency of 14th ribs, which was noted at 1,000 ppm on days
1-17 of gestation for 6 hours/day. As Wilkins-Haug 41 notes this has been the highest exposure
studied in the mouse model and is comparable to the inhaled toluene exposure which
produces euphoria in humans (500 ppm).
In 1991 we were approached by the medical department of Imperial Oil Limited to develop
a proactive approach of risk evaluation of their female workers. The paradigm developed
and used by us could be extrapolated to any other chemical operation. Its advantage is
in its proactive nature, which aims at informing workers and preventing potential fetal risks,
while also preventing unjustified fears which may lead women to quit their jobs or, in extreme
cases, even consider termination of otherwise wanted pregnancies.
Upon comparing the occupational literature that presented any quantifiable chemical
exposure dose or estimate of dose for any chemical with the IOL routine rating factors in the
Products and Chemicals Divisions, we could conclude that IOL chemical exposure levels
overall were lower than those reported in the literature. Of utmost importance is the need in
published occupational reports for at least some industrial hygiene documentation, namely
improved reporting of a quantifiable chemical exposure dose (for example, as implemented
and currently utilized by IOL) and ideally a standard and consistent way of reporting this in
the occupational literature.
20.3.6 OVERALL CONCLUSION
The Motherisk program is an information and consultation service for women, their families
and health professionals on the safety/risk of exposure to drugs, chemicals, radiation
and infection during pregnancy and lactation. Chemical exposure in the workplace is a common
source of concern among our patients and health professionals.
Occupational exposure to organic solvents during pregnancy is associated with an increased
risk of major fetal malformations. This risk appears to be increased among women
who report symptoms associated with organic solvent exposure. Although more prospective
studies will be needed to confirm our results, it is prudent to minimize women’s exposure
to organic solvents during pregnancy. This is most important during the first trimester
of pregnancy. Moreover, symptomatic exposure appears to confer an unacceptable level of
fetal exposure and should be avoided by appropriate protection and ventilation. Health care
professionals who counsel families of reproductive age should inform their patients that
some types of employment may influence reproductive outcomes.
Of utmost importance is the need in published occupational reports for some industrial
hygiene documentation. Specifically, improved reporting of a quantifiable chemical exposure
dose (for example, as implemented and currently utilized by IOL) and ideally a standard
and consistent way of reporting this in the occupational literature pertaining to human
reproductive toxicology.