In the March 2018 year, there were almost 60,000 live births registered in New Zealand, which was similar to the December 2017 year.

New Zealand’s total fertility rate in the December 2017 year and the March 2018 year was down to 1.81 births per woman, its lowest recorded level. The total fertility rate indicates, on average, the number of babies a woman would have in her lifetime if the age-specific fertility rates in a given period stayed the same throughout her life. Annual fluctuations in the total fertility rate do not necessarily indicate changes in family size, but rather changes in the timing of births.

The total fertility rate has only dropped below 1.90 births three times before, most recently to 1.87 in 2016. The replacement level is approximately 2.1 and reflects the average number of babies that women would need to have over their lifetime to maintain the size of the population.

The reducing birth rates have been mainly driven by trends among women aged 15-29 years, whose birth rates are now at record lows. Teen births only make up a small proportion of births – about 4 percent in recent times. However, they are of interest, as the teenage fertility rate has dropped to its lowest ever, with 15 live births per 1,000 women aged 15-19 in 2017 – just under half the 2008 rate of 33. In comparison, the teenage birth rate peaked in 1972, with 69 births per 1,000 women aged 15–19.

Within the 15 to 19 years age group, birth rates increase with age – from 2 per 1,000 at age 15, to 32 at age 19 in 2017. The birth rates for all ages in this group were less than half of that in 2008. Around 70 percent of births to those under 20 are to mothers who are 18 or 19 years old.

The numbers do not tell us why the teenage fertility rate has decreased, but it is occurring in other countries as well.  For example, the latest figures for Australia, show a declining teen fertility rate from 18 per 1,000 in 2008 to 11 in 2016, the latest year data is available.

It could be related to the general trend in the increasing age of women having babies.  The median age (half are younger and half older than this age) of New Zealand women giving birth was 30 years in 2017.  In comparison, the median age of women giving birth in the 1970s was 25 years.

Women aged in their early thirties have had the highest fertility rate since 2002, with 117 births per 1,000 women in 2017. The age group with the next highest fertility rate were those in their mid to late twenties with 93 births, followed by those in their mid to late thirties with 67 births. Women in their early forties have had a fertility rate of around 15 births per 1,000 women in recent years.

This piece was written for Family Planning by Statistics New Zealand. For further details on birth statistics in New Zealand, see the Stats NZ website:

• https://www.stats.govt.nz/news/birth-rate-down-to-record-low
• https://www.stats.govt.nz/information-releases/births-and-deaths-year-ended-december-2017

The above information is sourced from birth registrations data collected by the Department of Internal Affairs and processed by Stats NZ.