The objective that intended this work was to carry out an exploration on the evolution of the vital events associated to fertility (pregnancy, interruption of pregnancy, fetal death and live birth) and to value the effect that would produce the handling of some scenarios, concerning to these events, on this important demographic variable in the period from 1989 to 2004; besides it also intended to carried out a brief characterization of the evolution of the level of fertility in the lapse from 1970 up to 2008, associating it to different socioeconomic conjunctions. Three concrete scenarios were managed on Gross Reproductive Rate (GRR), apart from the one observed: the first one, supposes that all the effective pregnancies, would end up being born alive; the second differs from the previous one only for the fact of incorporating the effect of the fetal mortality, and the third deals with the additional quantity of born alive necessary to arrive to a value of unit in that indicator, maybe that of more interest. The results point out the falling tendency of almost vital events associated to fertility, with the exception of the menstrual regulations, in the period 1989- 2004; also the results for the first scenario locate the country at the level of some nations of the African continent and of Latin America that at the present time exhibit high levels of fertility; the second shows the poor effect of the fetal mortality in the fertility, while the third propose the idea that to reach at least the simple generational replacement level (Net Reproduction Rate equal unity) it would be necessary to reduce the proportions of pregnancy interruptions so that they don't exceed 40%. On the other hand an association was verified between the trajectory of GRR and the socioeconomic conditions of the country during the lapse between 1970 and 2008; it was showed how in periods that can be considered of smaller prosperity the value of GRR descends and in moments of relatively prosperity it rises, although it is expected that this indicator tends toward a kind of stabilization with a value below the generational replacement level.
Keywords: pregnancy interruption, gross reproduction rate, socioeconomic conditions, generational replacement level