Prolonged time to pregnancy in female workers exposed to ethylene glycol ethers in semiconductor manufacturing

Background. Previous research on reproductive effects of working in the semiconductor industry is limited and has produced conflicting results. Methods. This retrospective cohort study was designed to investigate the risk factors for female fertility in a wafer-manufacturing company of Taiwan in 1997. Waiting time to pregnancy and potential confounders were collected by face-to-face interview. Exposure was assessed by directors and senior engineers in manufacturing, administrative, and safety and health departments according to safety records, personnel records, and job histories from questionnaires, using a tiered exposure-assessment approach. Of a total 842 female workers, 720 (85.5%) participated. There were 292 pregnancies from 173 workers eligible for analysis. Relative fecundability (fecundability ratio, or FR) was calculated using Cox's proportional hazard models to evaluate the effect of occupational exposure to ethylene glycol ethers on female fertility. Results. Waiting time to pregnancy of female workers in the photolithography area was longer than that of those in the nonfabrication area (FR = 0.77; 95% CI = 0.45-1.32), and those who were potentially exposed to ethylene glycol ethers showed longer time to pregnancy compared with those not exposed (FR = 0.59; 95% CI = 0.37-0.94). Conclusion. This study provides further evidence that ethylene glycol ethers may cause female subfertility.