|Year : 2009 | Volume
| Issue : 2 | Page : 89-93
Physical hazards in employment and pregnancy outcome
Department of Community Medicine, Maulana Azad Medical College, Bahadur Shah Zafar Marg, New Delhi - 110 002, India
|Date of Submission||19-Mar-2008|
|Date of Acceptance||17-Oct-2008|
Department of Community Medicine, Maulana Azad Medical College, 2, Bahadur Shah Zafar Marg, New Delhi - 110 002
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Banerjee B. Physical hazards in employment and pregnancy outcome. Indian J Community Med 2009;34:89-93
| Introduction|| |
The past century has seen an enormous improvement in the political, social, and economic status of women, of which employment is an integral part.
Women workers require special protection while pregnant because of the following reasons: 
- The developing embryo may be more susceptible to noxious agents than the exposed mother.
- Females may be less suited for some work tasks than males.
- Pregnancy may decrease the capacity to cope with many work factors.
- Women tend to feed themselves less substantially than men.
| The Physiology of Work During Pregnancy|| |
Physical exertion has often been suggested as a risk factor for adverse pregnancy outcomes, ,,,,,,,,,,,,,,,,,,, which may occur due to various factors. ,,,
- Work involves muscle action, causing an increase of sympathetic vasomotor activity in working muscles proportional to the severity of work. Hence, when cardiac output increases rapidly during muscular activity, most blood goes to the working muscles and proportionately less arrives in the other viscera, which during pregnancy, includes the placental bed.
- With hard work there is an increased release of catecholamines with resultant arteriolar constriction. With chronic hard work, lactate accumulates making any unloading of lactate from the fetus more difficult.
- Sweating reduces plasma volume, which is an important determinant of uteroplacental blood flow. Circulatory blood flow in the uterus and placenta decreases in the standing position.
- Pronounced physical exercise may lead to hormonal disturbances, hypothermia, and nutritional deficits.
- Shift work and irregular work schedules could lead to a change in the circadian rhythm, which affects regulation of the ovulatory cycle with resultant menstrual irregularities. Whether such shifts also influence pregnancy outcome is unknown.
- Heavy lifting increases intra-abdominal pressure and this may provoke uterine contractions.
- Heat stress causes dehydration resulting in the release of the anti-diuretic hormone and oxytocin, which stimulates the uterus to contract.
Due to the combined effects of vasoconstriction, myometrial contraction, reduced plasma volume, and diversion of blood flow away from the placental bed, there is diminution of uteroplacental blood flow and resultant fetal hypoxia. This, along with possible hormonal imbalance, may have deleterious effects on the fetus.
| Reproductive Risk Factors|| |
Exposure to heavy lifting may be classified as follows: 
Grade Work exposure
0 - No heavy lifting at work
I - Heavy lifting (any weight), less than 10 times per week
II - Heavy lifting less than 12 kg, more than 10 times per week
III - Lifting 12 kg or more, 10 to 50 times per week
IV - Lifting 12 kg or more, more than 50 times per week
Shift work and inconvenient working hours
These may be defined as the following: 
Inconvenient working hours - any work outside the period of 0645 - 1745 hours.
Irregular working hours - work outside this interval, not beginning or ending at the same time each day.
Long working hours
Workers have been classified as full-time and part-time. 
Full time - those who work 35 hours or more per week
Part time - those who work less than 35 hours per week
Time of stopping work
Heavy lifting may have a negative effect on a child's birth weight if work is continued until the 32 nd week of pregnancy or longer. 
This may involve prolonged bending, stooping, twisting, or standing. Work may also be classified as sedentary or non sedentary based on the amount of physical work expended. ,
Other physical effort
Physical effort in any form that causes fatigue. 
This has been defined as job control, job demands, and work-related physical exertion. 
Exposure to the extremes of temperature, noise, and vibration. 
| Work Fatigue Score|| |
Several physical and ergonomic factors, studied as separate entities, have been considered as reproductive risk factors. Mamelle, et al. defined a fatigue scoring system by accumulating all such factors with a score of 1 allotted for the presence of each index factor as follows: ,
- Work on machine
- Physical exertion
- Mental stress
Another similar system included the following working conditions: 
- Standing for the majority of work
- Carrying heavy loads
- Working on an assembly line
- Performing a physically demanding job
| Women in Employment and Their Pregnancy|| |
A possible influence for the motivation for employment by women is related to personal fulfillment of economic necessity - "privilege effect" or "desperation effect". Studies conducted on women of varying employment status show multiple demographic and behavioral differences. Employed women are generally younger, more highly educated, have a higher family income, are less likely to be married, have half the number of pregnancies reported by housewives, begin prenatal care earlier, miss fewer antenatal appointments, and gain more weight during pregnancy. They smoke less, both early and late in pregnancy, but light and moderate alcohol consumption is often more. ,
The hypothesis that women's increased work participation may have significant health consequences is based upon two observations. First, women do not generally shed their housekeeping and child rearing responsibilities when they enter the workforce, resulting in exhaustion. Second, pregnant working women may come in contact with an environment that may damage the fetus. 
| Physical Work During Pregnancy and its Hazard to the Fetus|| |
Women in various occupations have been found to be at an increased risk of experiencing a fetal death. Of all the sectors observed, risk was highest for those employed in the textile industry. ,,,,,,,,,,,,,,,,
The significant work factors directly correlated with adverse pregnancy outcomes included: fewer household helpers, standing at work for more than 7 hours per day, working in hot environments, commuting, walking, and carrying and lifting heavy weight. ,,,
A meta-analysis has shown physically demanding work to be significantly associated with pre-term birth. Other occupational exposures significantly associated included prolonged standing, shift and night work, and a high cumulative work fatigue score. No significant association was found between long work hours and pre-term birth. 
Standing at work and lifting heavy weight, though often not significant, have been seen to be associated with pregnancy loss and pre-term birth, especially in women whose nutrition status is compromised. ,,,,,,,,,
Risk of pregnancy loss has been observed to be higher among women with a fixed evening work schedule in comparison with women with a fixed day schedule, and twice as high among those on a fixed night schedule. The highest abortion rate has also been seen in workers who reported irregular working hours and rotating shifts. ,, Effects of rotating shift work on both gestational age and birth weight have also been found to be significant. 
Women working more than 45 hours per week are 5 times more likely to report high stress as those working less than 35 hours per week. ,,,
Environmental influence on pregnancy outcome has also been observed. Long-term whole body vibration exposures and working in extremely cold environments can contribute to disturbances of pregnancy causing abortion and stillbirth. , Occupational noise above 85-90 dB was associated with a decline in birth weight. ,
Some studies, however, have not reported higher risks, and employed women sometimes have been observed to have fewer previous miscarriages or perinatal deaths when compared with housewives. Also, the higher rate of previous miscarriages among working women than non working women, observed in one study, had disappeared when adjusted for parity. ,,
The risk of employment on delivering a low birth weight infant has also been negated by many authors. No difference was observed in these aspects between economically active women compared with inactive women, or in women with stress, anxiety, depression, and physical strain due to employment, than in those without. ,,,
| Validity of the Studies|| |
Studies of occupational exposures and reproductive health have reported varied results. This may be due to the following reasons: 
- Many studies are small in terms of the number of women exposed and the number of abnormal outcomes.
- The number of potential association investigated is large and as a result some may appear 'statistically significant'.
- A large number of non-occupational factors, many still unknown, affect the pregnancy outcome.
- Reasons for traumatic events, such as fetal death or serious defect, may be influenced by the traumatic experience.
Several types of potential bias also threaten the validity of such studies. ,
1. Healthy pregnant worker effect
- Favorable social, economic, and behavioral aspects of employment, like income from employment, better health insurance coverage, better prenatal care, and a more healthy lifestyle, are expected to be associated with favorable pregnancy outcomes among working women.
- Women with severe illness or mental incapacity may be selected out of the workforce leaving healthier working women with the possibility of better reproductive outcomes.
- Women with a history of adverse reproductive outcomes avoid employment for fear of repeated pregnancy problems.
2. Unhealthy pregnant worker effect
- Women who have healthy infants may stop work while their children are young, whereas women who fail to produce a surviving infant may be more likely to continue working.
These studies are often affected by recall bias and 75% of recorded abortions are recalled. Recall failure is influenced by factors such as the time elapsed since the event, total number of births or spontaneous abortions, the woman's age at the time of pregnancy, times in a woman's life when abortions occur, and the gestational age of the fetus at the time of abortion. Medical treatment received and hospital admission might emphasize the event and facilitate recall. Social class and education are other factors that may affect the completeness of the recall. Also, there are chances of misrepresentation of exposure data obtained by the self-administered questionnaire. ,,
| Recommendations|| |
During work, some inevitable adverse conditions may arise. Various authors have suggested measures to make these conditions more bearable and less harmful for the pregnant worker and their children. ,,,, Accordingly, the following recommendations may be made:
- Food - Reproductive risks are more pronounced in malnourished women, therefore, supplementary nutrition may be given to all pregnant working women to provide a part of their daily calorie and protein requirement.
- Rest - Rest rooms should be provided near the workplace where pregnant women can rest when fatigued. Pregnant women should also be allowed 10 minutes rest after every 1 hour of work. Rush hours can be avoided by coming after the beginning of the shift and leaving after the shift is over.
- Leave - Leave rules should be brought to the knowledge of all workers and they should be advised to avail such leaves.
- Antenatal care - Antenatal clinics may be arranged within factory premises or several smaller establishments together may hold an antenatal clinic regularly. Women should be allowed paid time off to attend these clinics and travel assistance should be provided for referred cases. Investigations and medications should be provided by the employer. One health worker may be engaged to regularly visit the pregnant women.
- Intra natal and post natal care - In India, these are generally rendered by ESI hospitals. Vehicles should be provided to attend the hospital during an emergency. For others, traveling allowance should be sanctioned.
- Family planning - Such clinics may be held within the premises for distributing temporary contraceptive devices.
- Risk factors - Measures should be adopted to avoid exposure of pregnant women to work conditions considered to be reproductive risk factors. All female workers should be trained for working in all departments where women are usually posted. Pregnant women should be assigned work with the least physical strain, and allotted work in fixed day shifts only, throughout their pregnancy. Sitting arrangements, fans, cool drinking water, and ear muffs should be provided.
- Orientation programs - Such programs should be held regularly for all women workers for the purpose of generating awareness and motivating them to utilize available facilities. The employer and managerial and supervisory staff should have adequate knowledge of the issue and they should see that the facilities are being availed properly, without misuse by ineligible workers.
- Awareness of community - Mass media can be used to improve the knowledge of all employers and employees regarding reproductive health.
- Research -Reproductive research should be promoted. Governmental and non governmental research organizations should be given more assistance for work in this sphere.
| References|| |
|1.||Park's textbook of preventive and social medicine. 17 th ed. Jabalpur, India: M/S Banarsidas Bhanot Publishers; 2007. |
|2.||Chamberlain G. Effect of work during pregnancy. Obstet Gynecol 1985;65:747-50. |
|3.||Ahlborg G, Bodin L, Hogstedt C. Heavy lifting during pregnancy: A hazard to the fetus? Int J Epidemiol 1990;19:90-7. |
|4.||Axelsson G, Rylander R, Molin I. Outcome of pregnancy in relation to irregular and inconvenient work schedules. Br J Ind Med 1989;46:393-8. |
|5.||Banerjee B, Dey TK, Chatterjee P. Work related physical exertion and spontaneous abortion. Indian J Public Health 2005;49:248-9. |
|6.||Banerjee B. Work exposure during pregnancy and its hazard to the fetus. Indian J Occup Environ Med 2003;7:33-6. |
|7.||Banerjee B, Chatterjee P. Effect of maternal employment on the early neonate. Indian J Occup Environ Med 2002;6:169-70. |
|8.||Banerjee B, Dey TK, Chatterjee. Estimation of risk of pregnancy wastage due to lifting of heavy weight during pregnancy. Indian J Occup Environ Med 2002;6:13-5. |
|9.||Banerjee B, Chatterjee P, Dey TK. Perinatal mortality in employed women. Indian J Community Med 2003;28:112-6. |
|10.||Minja Kim Choe, Seung-Kwon Kim. Pregnancy wastage among married women in South Korea. Asian Population Studies 2007;3:37-55. |
|11.||Figα-Talamanca I. Spontaneous abortions among female industrial workers. Int Arch Occup Int Health 1984;54:163-71. |
|12.||Goulet L, Theriault G. Association between spontaneous abortion and ergonomic factors: A literature review of the epidemiologic evidence. Scand J Work Environ Health 1987;13:399-403. |
|13.||Florack EI, Zielhuis GA, Pellegrino JE, Rolland R. Occupational physical activity and the occurrence of spontaneous abortion. Int J Epidemiol 1993;22:878-84. |
|14.||McDonald AD, Armstrong B, Cherry NM, Delorme C, Diodati-Nolin A, McDonald JC, et al . Spontaneous abortion and occupation. J Occup Med 1986;28:1232-8. |
|15.||McDonald AD, McDonald JC, Armstrong B, Cherry NM, Nolin AD, Robert D. Prematurity and work in pregnancy. Br J Ind Med 1988;45:56-62. |
|16.||McDonald AD, McDonald JC, Armstrong B, Cherry NM, Delorme C, Nolin AD, et al . Occupation and pregnancy outcome. Br J Ind Med 1987;44:521-6. |
|17.||Vaughan TL, Daling JR, Starzyk PM. Fetal death and maternal occupation. J Occup Med 1984;26:676-8. |
|18.||Makowiec-Dcabrowska T, Seidlecka J. Physical exertion at work and the course and outcome of pregnancy. Med Pract 1996;47:629-49. |
|19.||Tamakoshi A, Ohno Y, Tomoda Y, Mizutani H, Kurauchi O, Maruyama T, et al . Maternal working status and low birth weight: Findings from a cohort study. Nippon Sanka Fujinka Gakkai Zasshi 1994;46:503-8. |
|20.||Kumar R, Kumar V. Effect of physical work during pregnancy on birth weight. Indian J Pediatr 1987;54:805-9. |
|21.||Ramji S. Socioeconomic and environmental determinants of perinatal and neonatal mortality in India. Indian Pediatr 1989;26:1100-5. |
|22.||Lajinian S, Hudson S, Applewhite L, Feldman J, Minkoff HL. An association between the heat-humidity index and preterm labor and delivery: a preliminary analysis. Am J Pub Health 1997;87:1205-7. |
|23.||Zenz C. Occupational medicine. Principles and practical applications. In: Dickerson BO, Horvath EP, editors. 2 nd ed. Pub Mosby; 1988. |
|24.||Chamberlain GV. Work in pregnancy. Am J Ind Med 1993;23:559-75. |
|25.||Savitz DA, Whelan EA, Rowland AS, Kleckner RC. Maternal employment and reproductive risk factors. Am J Epidemiol 1990;132:933-45. |
|26.||Magann EF, Nolan TE. Pregnancy outcome in an active-duty population. Obstet Gynecol 1991;78:391-3. |
|27.||Murphy JF, Dauncey M, Newcombe R, Garcia J, Elbourne D. Employment in pregnancy: Prevalence, maternal characteristics, perinatal outcome. Lancet 1984;1:1163-6. |
|28.||McDonald A. Work and pregnancy in epidemiology of work related diseases. In: McDonald C, editor. London: BMJ Publishing Group; 1995. p. 293-323. |
|29.||Mamelle N, Laumon B, Lazar P. Prematurity and occupational activity during pregnancy. Am J Epidemiol 1984;119:309-22. |
|30.||Mamelle N, Munoz F. Occupational working conditions and preterm birth: A reliable scoring system. Am J Epidemiol 1987;126:150-2. |
|31.||Gabbe SG, Turner LP. Reproductive hazards of the American lifestyle: Work during pregnancy. Am J Obstetr Gynecol 1997;176:826-32. |
|32.||Najman JM, Morrison J, Williams GM, Anderson MJ, Keeping JD. The employment of mothers and the outcomes of their pregnancies: An Australian study. Public Health 1989;103:189-98. |
|33.||Fenster L, Hubbard AE, Windham GC, Walker KO, Swan SH. A prospective study of work related physical exertion and spontaneous abortion. Epidemiology 1997;8:66-74. |
|34.||Senturia KD. A woman's work is never done: Women's work and pregnancy outcome in Albania. Med Anthropol 1997;11:375-95. |
|35.||Gold EB, Tomich E. Occupational hazards to fertility and pregnancy outcome. Occup Med 1994;9:435-69. |
|36.||Mozurkewich EL, Luke B, Avni M, Wolf FM. Working conditions and adverse pregnancy outcome: A meta-analysis. Obstet Gynecol 2000;95:623-35. |
|37.||Spinillo A, Capuzzo E, Baltaro F, Piazza G, Nicola S, Iasci A. The effect of work activity in pregnancy on the risk of fetal growth retardation. Acta Obstet Gynecol Scand 1996;75:531-6. |
|38.||Henriksen TB, Hedegaard M, Secher NJ, Wilcox AJ. Standing at work and preterm delivery. Br J Obstet Gynaecol 1995;102:198-206. |
|39.||Sternfield B. Physical activity and pregnancy outcome: Review and recommendations. Sports Med 1997;23:33-47. |
|40.||Koemeester AP, Broersen JP, Treffers PE. Physical workload and gestational age at delivery. Occup Environ med 1995;52:313-5. |
|41.||Infante-Rivard C, David M, Gauthier R, Rivard GE. Pregnancy loss and work schedule during pregnancy. Epidemiology 1993;4:73-5. |
|42.||Axelsson G, Rylander R, Molin I. Outcome of pregnancy in relation to irregular and inconvenient work schedules. Br J Ind Med 1989;46:393-8. |
|43.||Armstrong BG, Nolin AD, McDonald AD. Work in pregnancy and birth weight for gestational age. Br J Ind Med 1989;46:196-9. |
|44.||Xu X, Ding M, Li B, Christiani DC. Association of rotating shift work with preterm birth and low birth weight among never smoking women textile workers in China. Occup Environ Med 1994;51:470-4. |
|45.||Schenker MB, Eaton M, Green R, Samuel S. Self reported stress and reproductive of female lawyers. J Occup Environ Med 1997;39:556-68. |
|46.||Ceron-Mireles P, Harlow SD, Sanchez-Carillo CI. The risk of prematurity and small-for-gestational-age birth in Mexico city: The effects of working conditions and antenatal leave. Am J Public Health 1996;86:825-31. |
|47.||Savitz DA, Brett KM, Baird NJ, Tse CK. Male and female employment in the textile industry in relation to miscarriage and preterm delivery. Am J Ind Med 1996;30:307-16. |
|48.||Seidel H. Selected health risks caused by long-term whole-body vibration. Am J Ind Med 1993;23:589-604. |
|49.||Nurminen T. Female noise exposure, shift work and reproduction. J Occup Environ Med 1995;37:945-50. |
|50.||Hartikainen AL, Sorri M, Anttonen H, Tuimala R, Laara E. Effect of occupational noise on the course and outcome of pregnancy. Scand J Work Environ and Health 1994;20:444-50. |
|51.||Savitz DA, Brett KM, Dole N, Tse CK. Male and female occupation in relation to miscarriage and preterm delivery in Central North Carolina. Ann Epidemiol 1997;7: 509-16. |
|52.||Marbury MC, Linn S, Monson RR, Wegman DH, Schoenbaum SC, Stubblefield PG, et al . Work and pregnancy. J Occup Med 1984;26:415-21. |
|53.||Henriksen TB, Savitz DA, Hedegaard M, Secher NJ. Employment during pregnancy in relation to risk factors and pregnancy outcome. Br J Obstet Gynecol 1994;101:858-65. |
|54.||Barnes DL, Adair LS, Popkin BM. Women's physical activity and pregnancy outcome: A longitudinal analysis from the Philippines. Int J Epidemiol 1991;20:162-72. |
|55.||Jacobsen G, Schei B, Hoffman HJ. Psychosocial factors and small-for-gestational-age infants among parous Scandinavian women. Acta Obstet Gynecol Scand Suppl 1997;165:14-8. |
|56.||Zuckerman BS, Frank DA, Hingson R, Morelock S, Kayne HL. Impact of maternal work outside the home during pregnancy on neonatal outcome. Pediatrics 1986;77:459-64. |
|57.||Work and pregnancy. Br J Ind Med 1988;45:577-80. |
|58.||Axelsson G. Selection bias in studies of spontaneous abortion among occupational groups. J Occup Med 1984;26:525-8. |
|59.||Wilcox AJ, Horney LF. Accuracy of spontaneous recall. Am J Epidemiol 1984;120:727-33. |
|60.||Ahlborg GA Jr. Validity of exposure data obtained by questionnaire. Scand J Work Environ Health 1990;16:284-8. |
|61.||Bond MB. Role of corporate policy in the control of reproductive hazards of the workplace. J Occup Med 1986;28:193-5. |
|62.||Chamberlain G, Garcia J. Pregnant women at work. Lancet 1983;1:228-9. |
|63.||Dutta DC. Textbook of obstetrics. 6 th ed. Konar H, editor. Kolkata, India: Pub New Central Book Agency (P) Ltd; 2004. |
|64.||Indulski JA, Baranski B, Kowalski Z, Mikoajczyk H, Makowiec-Dabrowska T. Project for amending regulations regarding jobs prohibited to women. Med Pract 1992;43:453-7. |
|65.||Sareen IB, Tilak VW, Sharma M. Women and occupational health. Indian J Ind Med 1997;43:34-8. |
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