Revista de Medicina Desportiva (English) November 2018 - Page 10

consumption, overweight and obe- sity by the mother. Physical activity has an important role in the fight against excessive weight gain and on the pregnancy complications, like gestational diabetes and pre- eclampsia, being the relation less clear about the risk of PTD itself, which motivates this study. This systematic review included 41 studies (43 publications), where 20 studies were randomized and 21 of cohort, and most of the studies were published in Europe and in North America. The authors included any type of physical activity, that could be the practice of varied physical exercise, leisure activities or occu- pational activity. From the main results, it is highlighted that the superior levels of physical activ- ity during the free time during the pregnancy were associated with the statistically significant 14% decrease of the risk for PTD and for each increase of three weekly hours on leisure activities there was a 10% reduction of the relative risk for PTD. The authors concluded the existence of a not linear association between physical activity during pregnancy and the risk of PTD, where the lowest risk was for the period of 2-4 hours / week of physical activity (reduction of 15-16% on risk). However, they point out that this association must be seen with caution, since it only had statistical significance in the studies of cohort, but not in the ran- domized and controlled studies. The other types of physical activity and activity practice before pregnancy pointed in the way of risk reduction, but also without statistical signifi- cance, which was justified by the authors because of low power of the sample. As far as dose-response is con- cerned, the authors found evidence on the decreased risk for PTD with 2 to 4 hours per week of physical activity but didn’t find higher rates of reduction of the risk with supe- rior levels of activity. In this case, it is important to note that the number of studied cases involving superior levels of activity is scarce, being necessary more studies to be 8 november 2018 www.revdesportiva.pt possible to withdraw conclusions. There is, however, scientific evidence that levels of 5 to 7 hours / week of physical activity have benefits in the reduction of pre-eclampsia and gestational diabetes. About the limitations, although most of the studies have adjusted analyses to several confound- ers, and the meta-analyze hadn’t shown heterogeneity among the studies, the authors assume some interference of the confounders not measured, such as the diet. The fact that the different studies report the results in different measures turn the analyze more difficult. This paper points to some jus- tifications about the inverse rela- tionship between physical activ- ity and PTD, namely the fact that the practice of physical exercise is related with a better control of weight gain. However, this review demonstrated a significant reduc- tion of the risk associated solely with exercise, independently of body mass index of the pregnant women. So, it is concluded that the prac- tice of more physical activity by the pregnant women is related to the reduction of the risk for PTD, but some studies are needed to clarify the dose-response relationship and the association with the different types and intensities of the physical activity as well. It is always good to remind that physical exercise has good evidence for the preven- tion of the several complications of pregnancy, is useful and it is recom- mended to consider the global well- being of the pregnant woman, that should keep herself active through- out pregnancy. Full text can be red at www.revdesportiva.pt a. Student of the post-graduation course on sports medicine. Medical School of Porto (2018/2019) 1. D Aune, S Schlesinger, T Henriksen, OD Saugstad, S Tonstad. Physical activity and the risk of preterm birth: a systematic review and meta-analysis of epidemiological studies. BJOG. 2017 Nov; 124(12):1816-1826. The preterm delivery in Portugal It is a normal reality that also occurs in Portugal. A visit to several sites allows to find out some numbers. For example, in 2005 there were in Portugal 109399 live births and 7260 (6.6%) were PTD, this means, they were born before full 37 weeks of gestation. The text indicates that “these percentages have been kept stable for the last years”, where the twin pregnancy is the main cause. In the meanwhile, a news dated 06/2016 referred that “in 2014, 6393 preterm babies were born … and, of these, 816 (about 1%) were very premature (<32 weeks), which have the highest risk. In another text, it is stated that prematurity is the main cause of death during the first year of life, and it is the 2 nd cause before 5 years of age, but “the technological development and the differentiation in some hospitals” caused the increase of the survival rate. It is added, in this text, other risk factors: pregnancy at the extremes of age (<18 and >35 years of age), smoking habits, quick wear jobs and intense psychologi- cal stress. BR