Declining Irish fertility rates are compensated for by an increase in the number of immigrants with higher fertility rates.
This has contributed to the increasing birth rate in recent years, a study on behalf of the Eastern Regional Health Authority (ERHA) has found.
The analysis of maternity statistics found, however, that the short-term rise in the number of babies born in the eastern region over the next few years will be followed by a longer-term decline.
The drop in births could be as high as 20 per cent between now and 2016. The study was carried out by the Small Area Health Research Unit at Trinity College Dublin.
One of the more significant changes noted in the study is that women are increasingly having their first babies later, with the average age of mothers now at 30.1 years. Between 23,241 and 23,832 babies will be born in Dublin's maternity hospitals this year, rising to a maximum of 24,824 in 2003 and of 25,289 in the year 2007, before tapering off gradually, the study said.
"By 2016, the study estimates that between 18,580 and 23,170 births will be taking place in the eastern region [annually]," a spokeswoman said.
"Factors contributing to these figures include a combination of an ageing population and declining Irish fertility rates, coupled with a compensating increase in the numbers of immigrants with, initially, higher fertility rates."
Ireland has at present the highest birthrate in the EU, at 14.6 births per 1,000 last year.