| Objective: In order to investigate the influence of ergonomic factors (noise, high humility, shift, whole-body vibration, physical exertion, lifting or carrying heavy, dust, occupational stress and posture) on the reproductive outcomes which including time to pregnancy(the needed menstrual cycles from cessation of birth-control to clinic pregnancy, TTP), clinic spontaneous abortion (clinic pregnancy ended before 28 gestational week, SAB)and the living-birth抯 birth weight and gestational age. A well characterized prospective cohort of newly married textile women was followed. Method: Between August 1996 and August 2000, we investigated all newly married women textile workers with validated baseline questionnaire and established a cohort of newly married women for all eligible subjects. Eligible planning pregnant women in the newly married cohort would enter the pre-pregnant monitoring cohort when they stop using birth-control. They began to daily record a sheet of diary until they were clinic pregnant or up to a year. When all eligible subjects were clinic pregnant in the newly married cohort, we would investigate them every three-months and collect information about exposure and pregnant outcomes (such as clinic spontaneous abortion and living-birth). If the pregnant outcome was living-birth, we would extract the information such as baby抯 birth weight, sex and birth date from the hospital抯 records. The ergonomic factors were assessed by a hygienist based on each woman抯 workstation. Results: 1005 subjects had attended the baseline investigation and of them 956 were eligible. In the analysis of TTP, 578 planning pregnant women who were contributed a total of 2 1,923 cycles. Multivariate COX proportional hazard regression model were used to examine the individual and combined association of ergonomic factors and time to pregnancy with adjustment for major confounders including intercourse frequency. There was a dose-response relation between physical exertion and fertility. The fertility ratio of middle physical exertion to light is 0.72(95%CI: 0.51-1 .01), high to light is 0.61(95%CI: 0.39-0.96). Totally, 77 SAB and 635 clinic living birth were analyzed in the relation of SAB and ergonomic factors by using single factor and multi-factor Logistic regression. Occupational stress was associated with SAB both in single factor and multi-factor analysis(single factor: 0R1 .62,95%CL: 1.01-2.62 , multi-factor: 0R1 .56, 95%CI:0.94-2.58). Totally 614 living-birth attended the analysis of birth weight and gestational age. In the linear regression of birth weight, before and after adjusted gestational age, the effect of whole-body vibration, high humility and shift changing greatly, and in the linear regression of gestational age the effect of whole-body vibration and shift were obviously. In the logistic regression of lower birth weight (under the 20th percent of the whole birth weight distribution ) and earlier delivery(under the 20th percent of the whole gestational week distribution), high humility was the risk factor of lower birth weight after adjusted gestational age(OR=3.24,95%CI:1.10-9.53), and shift was the risk factors of earlier delivery(OR=2.86,95%CI: 1.1 6-7.00).Conclusion: In this textile women population, Physical exertion has dose-response relation with time to pregnancy. occupational stress was associated with SAB. high noise and high humility exposure were associated with decreased birth weight. Whole-body vib... |
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