Post-Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
Sports Med. 2009;39(11):961-75. doi: 10.2165/11317900-000000000-00000.
Preterm birth is a major reason for infant mortality and morbidity, representing a public health concern worldwide. Regular and voluntary physical activity is healthy behaviour that should be incorporated by everyone, including pregnant women. On the other hand, some women are exposed to highly demanding occupational physical activities during pregnancy that might represent a threat to the fetus and to their own health. This paper is a literature review of studies (1987-2007) on physical activity during pregnancy and its relationship to preterm birth. Although the effects measured by the studies are not strong and the evidence is impaired by many methodological flaws, it seems that recreational or leisure-time physical activities performed regularly provide protection against prematurity. Studies on occupational physical activities, especially standing for long periods, present contrasting results - some presenting standing as a risk factor, but most showing no association. Housework and other daily activities do not seem to be associated with preterm birth. Regardless of the methodological aspects of the studies reviewed, there is a chance that the real effect of occupational physical activity is being blurred by some underlying factors not easily measured in epidemiological investigations. Our conclusions do not reject the idea that working conditions might represent danger for the pregnancy outcome, but only raise the question that maybe the mechanisms through which employment-related physical activities have been considered up till now could be better and more thoroughly studied. Future studies should pay additional attention to psychological and socioeconomic characteristics, without neglecting biological plausibility.
早产是婴儿死亡和发病的主要原因，也是全世界关注的公共卫生问题。定期和自愿的身体活动是一种健康行为，每个人都应该进行，包括孕妇。另一方面，一些孕妇在怀孕期间从事高要求的职业体力活动，这可能对胎儿和自身健康构成威胁。本文是对 1987 年至 2007 年期间关于孕期身体活动及其与早产关系的研究进行的文献回顾。尽管研究中测量的效果并不明显，而且由于存在许多方法学缺陷，证据受到了损害，但似乎有规律地进行娱乐或休闲时间的身体活动可以预防早产。关于职业体力活动的研究，特别是长时间站立的研究结果相互矛盾——有些研究表明站立是一个危险因素，但大多数研究并未显示两者之间存在关联。家务劳动和其他日常活动似乎与早产无关。无论对所审查研究的方法学方面进行何种评价，都有可能是一些潜在的、在流行病学研究中不易测量的因素掩盖了职业体力活动的实际效果。我们的结论并不是要否定工作条件可能对妊娠结果构成危险的观点，只是提出这样一个问题，即到目前为止，人们认为与工作相关的体力活动可能需要通过更好和更深入的研究来加以探讨。未来的研究应该更加关注心理和社会经济特征，同时也不能忽视生物学上的合理性。
