This thesis included a systematic literature review, yielding studies on three employment categories: hairdressers, cosmetologists and laboratory workers. The original research examined pregnancy outcomes for Finnish singleton births between 1990 and 2010. The parameters were increased male gender, low birth-weight, high birth-weight, pre-term delivery, post-term delivery, small for gestational age, large for gestational age, stillbirth and early neonatal death. Finnish Birth Registry data included 507,659 prima gravida women who delivered singletons with at least 22 weeks’ gestation 1990- 2010. There were 12,854 hairdressers, 1841 cosmetologists and 3587 laboratory workers. Control populations: 40,405 teachers, 1968 musicians and 447,004 women-general population. When hairdressers were compared to the general public, there were three marginally statistically significant results for new-borns: SGA, (OR 1.01, 95% CI 1.00 - 1.02), LGA, (OR 1.02, 95% CI 1.00 - 1.03) and post-term delivery (OR 1.06, 95% CI 1.02 -1.11). Marginal increased statistically significant results for pooled effect size (ES) from the meta-analysis were found for LBW among hairdressers ES 1.083 (95% CI, 1.017-1.153) and SGA infants among hairdressers ES 1.077 (95% CI, 1.006-1.153). Hairdressers may be at a marginally increased risk of low birth weight and small size for gestational age. This may be due to occupational exposure.