Hydrocarbons, C5-8

Toxicity to reproduction: other studies

Administrative data

Endpoint:

toxicity to reproduction: other studies

Adequacy of study:

other information

Reliability:

4 (not assignable)

Data source

Reference

Title:

No information

Author:

Wennborg, H, Magnusson, LL, Bonde, JP and Olsen, J. (2005)|Congenital malformations related to maternal exposure to|specific agents in biomedical research laboratories. J.|Occup. Environ. Med, 47, 11-19.

Materials and methods

Principles of method if other than guideline:

Type: other: epidemiology study

Test material

Test material information

Constituent 1

Reference substance name:

Benzene

EC Number:

200-753-7

EC Name:

Benzene

Cas Number:

71-43-2

Molecular formula:

C6H6

IUPAC Name:

benzene

Results and discussion

Any other information on results incl. tables

"Major malformations" (as defined by the International Classification of Diseases, commonly represented by congenital heart anomalies and club foot) were present in 41/1803 (2.3%) of infants born to mothers from the (total) exposed population, and 23/1200 (1.9%) of the (total) controls (OR = 1.2).

Neural crest malformations affected 14/1803 (0.8%) and 8/1200 (0.7%) of the exposed and control groups, respectively (OR = 1.2).

There were 27/958 (2.8%) major malformations among solvent exposed pregnancies versus 23 (1.7%) among non-solvent users. Comment: dominator for non-solvent users is not given, but appears to include the total control population (n = 1200, including non-responders) and a subset of the exposed population (n = 155, responders) that was not exposed to solvents.  

The proportion of craniofacial and contruncal neural crest malformations among solvent users was 1.0% (n = 10) compared with 0.6% (n = 8) in pregnancies from the reference group.  Comment: denominators appear to be as above.

The proportion of major malformations was elevated if the mother has worked with benzene before the end of the second trimester (10/278 = 3.6%) versus that recorded after exposure to solvents other than benzene (17/680 = 2.5%) or non-exposed pregnancies (23/1355 = 1.7%).

An odds ratio of 2.3 was obtained for major malformations associated with benzene exposure at or around the time of conception (7/133; 5.3%), and an OR of 5.3 for neural crest malformations (5/133; 5.8%).

Applicant's summary and conclusion

Conclusions:

The authors conclude there is an elevated risk of craniofacial and contruncal neural crest malformations in pregnancies where the mother had worked with solvents, especially benzene, although the numbers are small and the result interpreted with caution. No measured information is available on individual exposure to the various laboratory agents (including benzene) covered by the investigation.