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Information about the Abortion Statistics

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Valid From: ..01/01/1980
To: .. Ongoing
Frequency: ..Annually

Purpose: As the principal agency responsible for processing and publishing abortion statistics in New Zealand, Statistics New Zealand seeks to provide information that meets the legal, public policy and community requirements for up-to-date official statistics.

General Information ..Method of Data Collection
For every induced abortion carried out in New Zealand, as approved under the Contraception, Sterilisation and Abortion Act 1977, an ASC Form No. 4 (Notification of Abortion) must be completed and forwarded to the Abortion Supervisory Committee (ASC) within one month of the abortion.

An abortion may only be performed in an institution licensed by the Abortion Supervisory Committee for this purpose.

The hospital or clinic send the completed ASC Form No 4 to the Tribunals Unit (a division of the Ministry of Justice). The Tribunals Unit provides the ASC with administrative services. The forms are then sent to Statistics New Zealand who collates abortions data based on information from the notification form. Errors or omissions are referred back to the Tribunals Unit who liaises with the hospital or clinic. When Statistics NZ has finished processing the forms they are returned to the Tribunals Unit.

The Population Statistics Unit is responsible for producing a range of standard tables and abortion rates (including international indices) required by the ASC. Statistics NZ delivers the annual abortion output report to the ASC at the same time as the annual HOTP and Media releases are made publically available.

All abortions notified by hospitals or licensed abortion clinics in New Zealand.

Statistics New Zealand Obligation
One of the functions of the ASC is "....To obtain, monitor, analyse, collate, and disseminate information relating to the performance of abortions in New Zealand....". Until 1997, abortion data was disseminated by the ASC in its annual report to parliament. From 1998, following discussions between the ASC and Statistics NZ, Statistics NZ was accorded the responsibility for the dissemination of abortion statistics. These statistics are disseminated through annual HOTP and media releases and the Statistics NZ website and publications.

Abortion data are aggregated annually and refer to December years.

Collection Unit

The Abortion Supervisory Committee
    Ministry of Justice
    Tahu o te Ture
    Tribunals Unit
    Private Bag 32001
    86 Customhouse Quay

    Ph (04) 462 6660

The questions on the current Notification of Abortion Form (ASC Form No.4)

Name of hospital
Hospital Record Number
Form 3A/3B Certificate Number
Name of Consultants (2) authorising the abortion
Name of Medical Practitioner performing the abortion
Estimated duration of pregnancy by dates scan and/or examination
Grounds for performing the abortion
Contraception used at conception
Complications (occurring immediately)
Date of termination

Information Regarding the woman
Ethnic group
Date of Birth
Health domicile code
Number of previous live births, still births, and miscarriages
Number of previous induced abortions

Grounds for performing the abortion (s.187A Crimes Act 1961 (as amended))
EITHER where pregnancy is NOT MORE THAN 20 weeks
  • That the continuance of the pregnancy would result in serious danger to (not being danger normally attendant upon childbirth)
    1. The life of the woman or girl
    2. Physical health
    3. Mental health

    The following considerations are also taken into account:
    - The age of the woman or girl concerned is near the beginning or the end of the usual childbearing years.
    - There are reasonable grounds for believing that the pregnancy is the result of sexual violation.
  • That there is a substantial risk that the child, if born, would be so physically or mentally abnormal as to be seriously handicapped
  • That the pregnancy is the result of sexual intercourse between -
    1. A parent and child; or
    2. A brother and sister, whether of the whole blood or of the half blood; or
    3. A grandparent and grandchild
  • That the pregnancy is the result of sexual intercourse that constitutes an offence against section 131(1) of the Crimes Act 1961
  • That the woman or girl is severely subnormal within the meaning of section 138(2) of the Crimes Act 1961

OR where pregnancy is OVER 20 weeks
  • That the miscarriage is necessary
    1. to save the life of the woman or girl
    2. to prevent serious permanent injury to her
      (i) physical health
      (ii) mental health

Output Variables

Output variables are pieces of individual information that can be extracted from the survey/output data. Often output variables can be cross tabulated with other output variables, for example sales by industry classification. The list below contains all current and past output variables which have been released for this survey/output.

Variable NameDescription
AgeAge of woman having the abortion
EthnicityEthnicity of woman having the abortion
Previous Live BirthsNumber of previous live births
Previous Induced AbortionsNumber of previous induced abortions
Duration of PregnancyEstimated duration of pregnancy (weeks)
Grounds for AbortionGrounds for performing the abortion
Regional CouncilRegional council area in which the woman usually lives

Changes in Output Variables over time

Guide to Interpreting Data

Summary of Changes to Survey/Output ..Significant Events Relating to Abortion Statistics

1936 Committee of Enquiry established under the chairmanship of D.G. McMillan. One of the key findings of this enquiry was that at that time one in five pregnancies resulted in an induced abortion.
1961 The oral contraceptive pill comes onto the New Zealand market.
1967 The British Abortion Act passed.
1974 The Auckland Medical Aid Centre Abortion Clinic opened.
1975 The Hospitals Amendment Act was passed.
1976 First year when reporting of an abortion became obligatory.
1977 The Contraception, Sterilisation and Abortion Act passed.
1978 There was a temporary closure of the Auckland Medical Aid Centre Abortion Clinic.
There was a significant outflow of women to Australia seeking abortions.
Public hospital abortion facilities opened in Auckland in late 1978.
From 1 April 1978, collection of abortion data became the responsibility of the Abortion Supervisory Committee.
1979 The outflow of women to Australia seeking an abortion continued.
The Auckland Medical Aid Centre Abortion Clinic was granted a new licence.
1980 Public hospital abortion facilities opened in Wellington.
1983 Statistics New Zealand agreed to process abortion statistics. The first set of abortion statistics processed by SNZ was for the 1983 calendar year.
1998 Statistics New Zealand took over the responsibility for officially releasing abortion statistics. The first media and HOTP releases contained abortion statistics for the 1997 calendar year.
1999 "Lived in New Zealand for the past 12 months" question added to the notification form.
2002 Marital Status question removed from notification form. Ethnicity question changed to align with the 2001 Census question.
2003 "Lived in New Zealand for the past 12 months" question removed from the notification form. New Zealand residency, country of birth and first arrival in New Zealand question added.
2004 Health domicile question added to the notification form, anaesthetic question removed.
2006 New Zealand residency, country of birth and first arrival in New Zealand question removed from notification form. From 1 January 2006 ethnicity will be coded according to the 2005 ethnicity classification.
2008 New Zealand resident, number of previous stillbirths and miscarriages questions added. Anaesthetic used question reintroduced.
2009 Fetal abnormality question removed.

Usage and Limitations of the Data ..Availability of Abortion Statistics
Reliable abortion data is available from 1980. Data prior to this date is available, however, the quality of this data is questionable.

Prior to the enactment of the Hospitals Amendment Act of 1975, there was no legal requirement to report the performance of abortion in New Zealand. The official statistics available prior to September 1975 were limited to the number of abortions reported in public hospitals. Abortion data was collected by the Department of Health and related to abortions carried out under the grounds set out in the Crimes Act 1961.

From 1 April 1978, data collection became the responsibility of the Abortion Supervisory Committee, and abortions were performed in accordance with the procedures set out in the Contraception, Sterilisation and Abortion Act 1977, and under the grounds specified in the 1977 and 1978 Amendments to the Crimes Act 1961. Because all legally induced abortions must be notified under the Hospitals Amendment Act 1975 it is assumed that these data provide a complete record of all such abortions performed in New Zealand.

Regional Analysis
Up until 2004 abortion data was processed for the institution where the abortion was performed and not by the usual residence of the woman. This made it problematical to produce meaningful data on the prevalence of abortion in different regions, as the place at which an abortion is performed may be some distance from the usual residence of the woman concerned.

(The equality of access to abortion facilities throughout New Zealand was a major issue raised by the Abortion Supervisory Committee in their 1999 report to Parliament. They are concerned that many provincial areas either do not offer an abortion service or offer a limited service. This means that women who qualify for an abortion may have to travel to another region.)

In 2004, a new question asking for 'domicile code' was added to ASC Form No.4. As a result, abortion statistics by regional council area are now available from Statistics New Zealand on request. However, due to different rates of 'not specified region' across hospitals, regional data should be interpreted with care. This is the only subnational data currently available.

Ethnic Analysis
An analysis of abortion rates by ethnicity is fraught with classification problems as well as by an apparent lack of comparability between the numerators and the denominators used in calculating the abortion indices.

Abortion data is drawn from the ethnic question used in the Abortion Notification Form. The ethnic question asked on the form has changed over time. The ethnic question asked up until 2001 differed from that used in the Census of Population, which provides the exposed-to-risk population (the denominator used in the calculation of abortion rates). While census encourages multiple response, the abortion notification form tended to elicit a single ethnic response. The effect of these differences will be most noticeable in ethnic groups where the level of multiple ethnicity is relatively high, such as the Mäori and Pacific populations, and lowest for groups that are largely recent immigrants to New Zealand (primarily people with a single ethnic background). [The Census form captured more females of mixed ethnicity than the Abortion Notification Form. Consequently, demographers were faced with the formidable problem in the choice of denominator for calculating ethnic abortion rates. The level of abortion rate is directly affected by this choice, in some cases, quite substantially so.]

From 2002, the ethnic question on the Abortion Notification form aligns with the 2001 Census question on ethnicity. Therefore, ethnic data from 2002 will not be strictly comparable with ethnic data for earlier years.

From 1 January 2006 ethnicity will be coded according to the 2005 ethnicity classification. The new classification consists of six broad ethnic groups (European, Mäori, Pacific, Asian, MELAA (Middle Eastern, Latin American and African) and Other) compared with five under the previous classification (European, Mäori, Pacific, Asian and Other). In addition, a new ethnicity 'New Zealander' has been created within the Other group. Previously 'New Zealander' type responses (eg Kiwi) were coded to New Zealand European.

Around 98–99 percent of abortions are performed because of serious danger to the mental health of the woman.

Duration of pregnancy
Duration refers to the Xth week not complete weeks. For example, 7 weeks and 5 days is recorded as 8 weeks.

Related Data Sources ..

Sampling Errors ..None - no sampling involved

Non-sampling errors Processing Errors
All abortion notification forms are independently coded and processed twice. The output files are then compared and any differences corrected.

Non-processing Errors
There is always the chance of non-processing errors happening but quality control measures are in place. These include:
a) Verification of outliers.
b) Checking for valid codes.
c) Following up missing responses.

Caveats on Release ..In order to comply with Statistics New Zealand's confidentiality protocols, some categories are collapsed or aggregated in tables and datasets.

    Catalogue & Reference Numbers

    HOTP:ISSN 1178-0193

    Other Comments

    Classification(s) used


    Classification Versions

    Classification Type

    AGE - Age - New Zealand Standard Classification


    NZ Standard

    ETHNIC05 - Ethnicity New Zealand Standard Classification 2005



    REGC05 - Regional Council 2005


    NZ Standard

    AGEGPS - Age - 5 Year Groupings



    Glossary of Terms

    Age-specific A measure relating to an age group. Age-specific rates are commonly calculated for fertility, mortality, marriage, marriage dissolution and abortion.
    AbortionFoetal loss excluding stillbirths, usually during the first 20 weeks of gestation. Induced abortions are those initiated voluntarily with the intention of terminating a pregnancy. All other abortions are called spontaneous, even if an external cause is involved such as injury or high fever.

    All abortion statistics and derived abortion rates released by Statistics New Zealand are based on the number of legally induced abortions. No information is available on spontaneous or illegal abortion.
    Abortion Rate (Crude)The number of induced abortions per 1,000 mean estimated population.
    Abortion Rate (General)The number of induced abortions per 1,000 mean estimated number of women aged 15–44 years.
    Abortion RatioThe proportion of pregnancies terminated by an induced abortion. From 2007, Statistics New Zealand's standard for abortion ratios is the number of induced abortions per 1,000 known pregnancies (live births, stillbirths and induced abortions combined).
    However, different abortion ratios can be calculated depending on data availability (especially of lagged births for international comparisons). These include:
    1. the number of induced abortions per 1,000 live births
    2. the number of induced abortions per 1,000 live births occurring six months later
    3. the number of induced abortions per 1,000 induced abortions and live births
    4. the number of induced abortions per 1,000 induced abortions and live births occurring six months later.

    Care needs to be taken when comparing abortion ratios to ensure that consistent definitions are used.
    Total Abortion RateThe average number of abortions that a woman would have during her life if she experienced the age-specific abortion rates of a given period (usually a year). It excludes the effect of mortality.

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    Statistics New Zealand gives no warranty that the information or data supplied contains no errors. However, all care and diligence has been used in processing, analysing and extracting the information. Statistics New Zealand shall not be liable for any loss or damage suffered by the customer consequent upon the use directly, or indirectly, of the information supplied in this product.
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