[Effects of exposure to low-level benzene and its analogues on reproductive hormone secretion in female workers].

OBJECTIVE

To study the effects of exposure to low level of mixed benzene on reproductive hormone secretion during menstrual cycle in female workers.

METHODS

Concentrations of benzene, toluene and xylene in the expiratory air of 50 exposed female workers from their breathing zone were determined with gas chromatography. Their menstrual cycles of 50 exposed workers and 35 internal control and 35 external control workers were studied prospectively. Urine pregnandiol-3-glucuronide (PdG), follicle stimulating hormone (FSH) and estrone conjugate (E1C) were measured by enzyme immunoassay.

RESULTS

Mixed benzene existed mainly in the form of low-level benzene in the air of workplaces, with a detection rate of 29.10% at an average level of 8.88 (0.90-876.47) mg/m3, and 21% of measurements exceeded the national maximum allowable concentration with the highest one as 20.91 folds high as that of the national hygienic standard. Length of luteal phase in the exposed group (13.7 +/- 1.5) days was significantly shorter than that in the internal and external control groups (14.5 +/- 1.2) days and (15.2 +/- 1.1) days (P < 0.05 or P < 0.01). Urine level of E1C before ovulation, that of FSH at early follicular phase and that of PdG in luteal phase after ovulation in the exposed group were significantly lower than those in the internal control group (P < 0.05 or P < 0.01).

CONCLUSION

Exposure to low level of mixed benzene in workspaces could interrupt the function of hypothalamic-pituitary-ovarian axis and affect their normal levels of FSH, PdG and E1C.