Natality and the changing pattern of seasonality of births in the province of Teramo (Abruzzo, Italy: 1500-1871).

Reconstruction of human ecosystems and their stability over time provides knowledge of the processes of adaptability developed by isolated communities. Seasonality of vital events is a good indicator of the effects of different 'traditional' lifestyles, which in turn depend on the ecological context in which a population developed specific subsistence models. Seasonality of births reflects the cultural attitude towards the best time to conceive, in relation to work activities and loads; the latter may also affect physiological functions related to fertility. The present research concerns gross birth rates and seasonality of births and conceptions during four centuries in south-central Italy. Birth rates were between 33.0 and 36.5 per 1000. The pattern of seasonality of births and, by extension, of conceptions defines a southern-type agricultural area for the earlier periods. However, it also shows a progressive shift towards an increasing concentration of conceptions in spring-summer--namely from April to August--with a large increase in summer in the 19th century with respect to the previous periods. The new 19th century pattern is reported by Crisafulli, Dalla Zuanna & Solero (2000) as being representative of the central Adriatic region, a geographical classification to which Abruzzo can also be attributed.