The number of babies born in the first quarter of this year was down by 9 per cent on the same period last year.
Figures published by the Central Statistics Office show there were 17,563 births registered in the first three months of the year compared to 19,313 last year.
This represents an annual birth rate of 15.3 per 1,000 of the population, some 1.6 below the birth rate for the first quarter of 2012.
Fingal, the local authority area for north Dublin, recorded the highest birth rate of 19.6 per 1,000 population, while Donegal recorded the lowest birth rate at 11.4 per 1,000 population.
The CSO said there were 6,406 births registered as outside marriage or civil partnership, accounting for 36.5 per cent of all births. Of these, 3,685 births were to unmarried parents with the same address, or 21 per cent of all births.
Limerick city had the highest percentage of births outside marriage at 58 per cent, while Leitrim had the lowest at 22 per cent.
During the first quarter of 2013, some 8,347 deaths were registered - an increase of 4.6 per cent on the number registered in the first quarter of last year.
This represents a death rate of 7.3 per 1,000 population, the CSO said. It was a slight increase on the rate of seven per 1,000 population in the corresponding quarter last year.
Of those who died, 4,140 were male and 4,207 were female. Over a third - 33.5 per cent - of all deaths in the quarter were due to circulatory disease and 27.3 per cent were due to cancer. A total of 13 per cent were due to respiratory disease and 4 per cent were attributed to external causes, including accidents and suicides. Of the 103 deaths from suicide in the quarter, 88 were male and 15 female.
Some 55 infant deaths were registered in the first quarter, giving an infant mortality rate of 3.1 deaths per 1,000 live births. There were 36 neonatal deaths (deaths of infants aged under four weeks) - a neonatal death rate of two per 1,000 live births.
The CSO said the annual death rate for those aged 65 and over was 49.4 per 1,000 compared with a rate of 48.5 in the corresponding quarter of last year.
There has been a 14 per cent decrease in that rate since 2,004, when it was 57.5 per 1,000.