Fetal and Infant Deaths 2015

Summary

These tables present a summary of fetal and infant deaths, with a focus on deaths and stillbirths registered in 2015. Information presented includes demographic information (eg, ethnicity and sex), cause of death, gestation and birthweight, as well as deaths classified as sudden infant death syndrome (SIDS) and sudden unexpected death in infancy (SUDI).

This dataset is a continuation of the Fetal and Infant Death series. In editions of this series prior to 2012, individuals who were not identified as Māori or Pacific were presented as being part of the 'Other' ethnic group (eg, NZ European, Chinese, Indian, Middle Eastern, Unknown). Since 2012, individuals of Asian ethnicity (but not Māori or Pacific) are grouped as 'Asian' and all other individuals are grouped as 'European or Other'.

As in the 2014 edition, this 2015 edition includes more detailed breakdown of the gestation and birthweight categories to provide further insight. Rates for district health boards (DHBs) are graphed with error bars that represent 99% confidence intervals. Caution is advised when comparing these results with editions prior to 2014, which provided 95% confidence intervals.

Key findings for 2015

Overview

• There were 384 fetal deaths and 266 infant deaths registered in 2015.
• This equates to a fetal death rate of 6.1 per 1000 total births and an infant death rate of 4.3 per 1000 live births.
• Between 1996 and 2015, there was a statistically significant decrease in the infant death rate. The rate fell by 41%, from 7.3 to 4.3 per 1000 live births. This decrease was primarily due to a notable decrease in post-neonatal deaths.
• Over the same time period, the fetal death rate fluctuated between 6.0 and 8.5 per 1000 total births.

Ethnic group

• The fetal death rate was highest in the European and Other ethnic group in 2015 (6.5 per 1000 total births), followed by the rate in the Asian and Pacific peoples ethnic groups (both 6.1 per 1000 total births). The rate was lowest in the Māori ethnic group (5.6 per 1000 total births).
• In 2015, the fetal death rate was 16–20% lower than the rate for the previous five-year period (2010–2014) in the Māori, Asian and Pacific peoples ethnic groups. The fetal death rate was similar to the rate for the previous five-year period in the European and Other ethnic group.
• The infant death rate was highest in the Pacific peoples ethnic group (7.1 per 1000 live births). Rates were lower in the Māori, Asian and European or Other ethnic groups (4.9, 4.3 and 3.2 per 1000 live births, respectively).
• In 2015, the infant death rate was approximately 25% lower than the rate for the previous five-year period in the Māori and European and Other ethnic groups. Infant death rates in the Pacific peoples ethnic group were 3% lower than the rate for the previous five-year period. The rate in the Asian ethnic group was 17% higher than the rate for the previous five-year period.

Maternal age group

• The fetal death rate in 2015 was highest for babies of older women giving birth (9.2 per 1000 total births for the 40+ years age group) followed by babies of young women (9.0 per 1000 total births for the <20 years age group).
• The trend in 2015 was similar to previous years with higher fetal death rates seen in babies of young and older women and lower rates seen in babies of women aged 20–39 years.
• Babies of young women (<20 years age group) had the highest infant death rate, at 8.1 per 1000 live births. The rate was lower for all other age groups, between 3.8 and 4.4 per 1000 live births.
• Infant death rates in 2015 increased by 9% for babies of women aged 30–34 years, compared to rates for the five years previous (2010–2014). Rates in 2015 decreased by 11–36% for babies of women in all other age groups, compared to the rates for the previous five years.

Socioeconomic deprivation

• In 2015, the fetal death rate was highest in the most deprived areas (quintile 5, 7.2 per 1000 total births).  There was no pattern in fetal death rate across the deprivation quintiles.
• As with the previous five-year period (2010–2014), infant death rates in 2015 generally increased with increasing level of deprivation. The infant death rate for the most deprived areas (quintile 5, 5.8 per 1000 live births) was nearly twice the rate of the least deprived areas (quintile 1, 3.0 per 1000 live births).

Gestation

• Approximately 77% of fetal deaths and 60% of infant deaths registered in 2015 were preterm (<37 weeks’ gestation), the majority of which were very preterm (<28 weeks’ gestation).

Birthweight

• Approximately 60% of fetal deaths registered in 2015 had a birthweight of less than 1000g, most of which had a birthweight of less than 500g. Approximately 40% of infant deaths had a birthweight of less than 1000g, and these were spread between the <500g and 500–999g birthweight groups.

District health board region

• There was a wide range of fetal and infant death rates across district health board regions (DHBs) in 2015.
• West Coast DHB had the highest fetal death rate (12.7 per 1000 total births, 5 deaths) followed by Tairāwhiti DHB (8.1 per 1000 total births, 6 deaths). The lowest fetal death rate was in South Canterbury DHB (1.5 per 1000 total births, 1 death). These rates were based on low numbers (please refer to the note below).
• Counties Manukau, MidCentral and Waikato DHBs had the highest rate of infant deaths (all 6.3 per 1000 live births), 1.5 times the national rate.

Cause of death

• Approximately 74% of fetal deaths had a cause of death in the ICD-10 chapter group ‘Certain conditions originating in the perinatal period (P00–P96)'.
• The most common specified cause of fetal death being ‘Slow fetal growth and fetal malnutrition (P05)’, followed by ‘Disorders related to short gestation and low birth weight, not elsewhere classified (P07)’.
• ‘Fetal death of unspecified cause (P95)’ accounted for 42% of all fetal deaths.
• ICD-10 chapter groups ‘Certain conditions originating in the perinatal period (P00–P96)’ and ‘Congenital malformations, deformations and chromosomal abnormalities (Q00–Q99) accounted for 47% and 26%, respectively, of infant deaths.
• The most common specified cause of infant death was ‘Disorders related to short gestation and low birthweight (P07)’ (16%).

Sudden unexpected death in infancy (SUDI)

• There were 41 sudden unexpected death in infancy (SUDI) deaths in 2015, including 25 sudden infant death syndrome (SIDS) deaths. The SUDI deaths included 22 males and 19 females.
• The SUDI rate in 2015 (0.7 per 1000 live births) was half the rate in 2000 (1.4 per 1000 live births).
• In the five-year period, 2011–2015, the SUDI rate for babies in the Māori ethnic group was statistically significantly higher than the rate for babies in the Asian and European or Other ethnic groups, but not the rate for babies in the Pacific peoples ethnic group. The SUDI rate for babies born in the most deprived areas (quintile 5) was statistically significantly higher than the rate for all other deprivation quintiles.
• During this same period, 2011–2015, SUDI rates were generally higher among babies born with a low birthweight (2.3 and 2.4 per 1000 live births for those with a birthweight between 1000g–1499g and 1500g–2499g). SUDI rates were also generally higher among babies born to young mothers under 20 years (2.2 per 1000 live births), and at 28–31 and 32–36 weeks’ gestation (2.2 and 2.1 per 1000 live births, respectively). The highest SUDI rate was in Tairāwhiti DHB (2.2 per 1000 live births). Waitemata DHB had a rate that was statistically significantly lower than the national rate.

Note: The number of fetal and infant deaths in New Zealand is small and may cause rates to fluctuate markedly from year to year. Rates derived from small numbers should be interpreted with caution.