Birth weight is the single most significant determinant of infant mortality and the chances of a newborn to experience healthy development. Low birth weight also appears to be related to higher risks of several important chronic conditions, such as ischemic heart disease, non-insulin-dependent diabetes, and cancer in adults. Thus factors that influence in utero growth and birth weight may have a serious effect on health outcomes many years later in life. Analysis of seasonal variations in birth weights may enable us to suggest specific factors that influence this measure. In this review we summarize the literature on seasonal variations in birth weight. Although causes of seasonal variation in developing regions are more clearly understood, it is not yet clear which factors affect apparent seasonal variation in birth weight in developed countries. In our analysis we observed a pattern of seasonal variations in developed countries that differed between low-, middle-, and high-latitude countries, and we suggest several mechanisms that may be responsible for this diversity. Namely, we suggest that in middle-latitude climates, the large annual temperature range may cause low birth weights during summer, whereas in high- and low-latitude regions variations in sunlight exposure between seasons may contribute to low birth weights apparent during winter. Identification of the suggested causal environmental factors may have public health implications in the development of primary prevention programs for low birth weight and macrosomia in developed countries.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 81 • No. 4