en Occupational Medicine Occupational Medicine Original Research Original Research <p> <strong> Background: </strong>Chemicals are among risk factors that can affect women's reproductive system. This study is aimed to investigate the association of occupational exposure to a mixture of organic solvents with menstruation disturbances and hormonal changes among female workers. </p><p> <strong> Methods </strong>: Female workers of a pharmaceutical company were divided into three groups of non-exposed, low-exposed and highly-exposed to a mixture of organic solvents (formaldehyde, phenol, N-hexane, and chloroform) based on workplace measurements. Menstrual disturbances (in terms of short cycles, long cycles, irregular cycles, and bleeding or spotting between periods) and mean of hormone levels (including follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, prolactin, estrogen and progesterone levels) were compared between these three groups. For investigating associations, logistic regression was performed. </p><p> <strong> Results </strong>: Our study showed that mean length of cycles, duration of bleeding, and amount of flow and also prevalence of long cycles, irregular cycles, and bleeding or spotting between periods were higher in exposed groups (p≤0.05). Odds ratio for prevalence of menstrual disturbances in the low exposure group and high exposure group were 9.69 (p=0.001) and 3.40 (p=0.002) respectively compared to the reference group. Estrogen and progesterone levels were not affected (p> 0.05), but other hormones levels were significantly disturbed in the exposed groups compared with the non-exposed group (p=0.001). </p><p> <strong> Conclusion </strong>: Occupational exposure to the mixture of organic solvents may be associated with the increase of menstrual disorders and hormonal changes in female workers. Based on our findings, periodic evaluation of reproductive system of female workers in pharmaceutical companies is recommended. </p> Women, Occupational exposure, Solvents, Menstruation disturbances, Hormones. 1055 1064 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-766&slc_lang=en&sid=1 Somayeh Hassani sh9612003@yahoo.com 200319475328460014529 200319475328460014529 No Telemedicine Research Center, National Research Institute of Tuberculosis & Lung Diseases (NRITLD), ShahidBeheshti University of Medical Sciences, Tehran, Iran. Mohamad Namvar mnamvar@yahoo.com 200319475328460014530 200319475328460014530 No Occupational Medicine Department, School of medicine, Iran University of Medical Sciences, Tehran, Iran Maryam Ghoreishvandi maryam_ghoreishvandi@yahoo.com 200319475328460014531 200319475328460014531 No Islamic Azad University Pharmacology of Sciences, Tehran, Iran. Mirsaeed Attarchi msattarchi@yahoo.com 200319475328460014532 200319475328460014532 No Occupational Medicine Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran; Brain and Spinal cord injury research center (BASIR), Tehran University of Medical Sciences, Tehran, Iran. Majid Golabadi golabadi_m@yahoo.com 200319475328460014533 200319475328460014533 No Occupational Medicine Department, School of medicine, Iran University of Medical Sciences, Tehran, Iran. Seyed Mohammad Seyedmehdi mseyedmehdi@sbmu.ac.ir 200319475328460014534 200319475328460014534 Yes Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis & Lung Diseases (NRITLD), ShahidBeheshti University of Medical Sciences, Tehran, Iran. Mahshad Khodarahmian 200319475328460014535 200319475328460014535 No Occupational Medicine Department, School of medicine, Iran University of Medical Sciences, Tehran, Iran.