Fertility in a prospective Canadian cohort of women in the welding and electrical trades.

OBJECTIVES

To determine the effects of work exposures on fertility in tradeswomen.

METHODS

Women apprenticed in welding and electrical trades across Canada were recruited (2011-2017) to a prospective cohort and contacted every 6 months for up to 5 years. At each contact, participants provided information on conceptions, sexual activity, birth control and pregnancy attempts. Occupational exposures to ergonomic factors and, for welders, to metals and dust in welding fume were estimated from task-specific questionnaires. The OR of clinical infertility for work in welding was estimated. Time ratios (TR), relative times to conception, were estimated for first pregnancy in an accelerated failure time (AFT) regression with a log normal distribution of the hazard, to assess the relation of exposure to conception.

RESULTS

885 women were recruited, 447 in welding and 438 in electrical trades. 96 reported a period of clinical infertility (prevalence 10.8%) with 70/96 infertile since joining the trade. There was no excess in welders (OR=0.81 95% CI 0.49 to 1.33). 372 women were nulliparous and met selection criteria for further analysis. In the final multivariable model for welders, TR was increased with working >8 days without a rest day (TR=3.06 95% CI 1.03 to 9.05), reporting hand-arm vibration for >1 h/day (TR=3.06 95% CI 1.13 to 8.34) and with increasing aluminium exposure (TR=1.38 95% CI 1.05 to 1.80). Among electrical workers, TR was increased in those working above shoulder height for ≥2 h/day (TR=1.88 95% CI 1.19 to 2.97).

CONCLUSION

Work in welding did not increase the risk of clinical infertility, but time to first pregnancy reflected preventable work exposures.