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The article contains formulae for real fertility rate (RFR), functional and calendar-related pregnancy intervals. RFR is proposed as the criteria in the assessment of occupational factors' influence on the reproduction function in couples not using contraceptives. The simultaneous reproduction assessment with two indices involved (real fertility and birthrate) made it possible to evaluate the role of the occupational and social factors in human reproduction in the region. The agricultural female workers surveys showed that RFR remained stable at the time of examinations and births, taking account of the age, in women engaged in beet raising, cattle breeding and employees, who had been working in different labour conditions for 40 years. Within the same period of time, birth rates in the beet-raisers were markedly higher as compared with the employees.To evaluate the indices of physiological fertility in female agricultural workers, the outcomes of 24,153 pregnancies registered in the period from 1943 to 1982 in various beet growing and animal breeding regions of Ukraine were analyzed. More than one half of all pregnancies (63.9%) were recorded in women 30 years old. On average, a woman had 5.05 pregnancies; 47.4% of pregnancies terminated in normal delivery, 48.3% in abortion, and 3.7% in miscarriage (0.6% were extrauterine pregnancies). Average duration of the active ovarian function (from the onset of menstruation to the menopause) was 33.0 years. Occupational hazards included physically demanding work, exposure to dust, pesticides, fertilizers, and animal feed. It was suggested that the factual fertility is best characterized not by the birth rate but by the functional and calendar interval between pregnancies coupled with fertility coefficients (intensity of conceptions in unit of time) in women who did not use the contraceptive agents. For the given cohort, the functional interval between conceptions (refractory period) and actual fertility rate (AFR) were calculated. During the most active child bearing period (up to 40 years of age), the AFR was 5.27% in beet growers, 6.83% in animal breeders, and 6.04% in white collar workers. For the entire child bearing period (from 17 to 50 years of age), AFR ranged from 3.36 to 4.99%. The functional and calendar intervals between pregnancies showed gradual increase with age (from 10.1 months to 200 months). In a 25-29-year-old group, the interval between pregnancies was 17,1 months for beet growers, 12.0 months for animal breeders, and 18.7 months for white collar workers. |
