The number of multiple births has almost doubled since the mid-1990s as Ireland's population boomed, it has been revealed.
Latest figures show more than 1,100 sets of twins were delivered in 2007, with 26 sets of triplets and one set of quadruplets born.
The rate has steadily grown since just 574 sets of twins and 13 sets of triplets arrived in 1993.
The Central Statistics Office (CSO) final report on vital statistics for 2007 revealed more babies were born in the month of August - 6,520 - than any other time of the year.
Despite this, maternity hospitals dealt with the largest number of deliveries per day in the run-up to Christmas, with 783 babies born between December 19 and 21. Some 317 mothers suffered still births in the year.
Official figures showed the start of Ireland's recession-proof baby boom, in 2007, saw 71,389 births - 36,487 boys and 34,902 girls - up from 65,425 in 2006. Approximately 75,000 were delivered in 2008, with almost 57,000 born in the first nine months of 2009. Complete figures for last year are due next month.
The CSO also reaffirmed that Ireland's fertility rate was the highest in the EU in 2007. Women had an average 2.05 children that year, closely followed by France and England at 1.98 and 1.92. Slovakia, Romania and Poland had the lowest. Ireland's fertility rate peaked at 3.27 in 1977. In 2007 the birth rate was 16.5 per 1,000 of the population, compared with 13.9 in Northern Ireland, 12.8 in England and Wales and 11.2 in Scotland.
Four out of 10 new arrivals were to first-time mothers, but figures showed Irish mothers were opting for larger families with 10% of newborns already having at least three siblings. Just six in every 1,000 women giving birth opted for a home delivery.
Elsewhere, a third of all births, and 44% of first births, were outside marriage - with more than half of all newborns in Limerick City delivered outside wedlock. The Iona Institute, a pro-marriage, pro-religion organisation, said the State has done little or nothing in recent years to promote marriage.
David Quinn, director, said: "The fact that close to half of first births now take place outside marriage highlights the urgent need for the Government to begin strongly promoting marriage again if it is really interested in child welfare. Study after study highlights the benefits of marriage, especially for children but also for adults. Ideally children should be raised by a loving mother and father and marriage provides the best chance of this taking place."