By Joseph M. Boden

Joseph M. Boden explores how research can inform change with regards to abortion law reform.

In October 2018, the Law Commission released a briefing paper (1) examining possible changes to the Abortion Law in New Zealand.  Currently, abortion is allowed under the Crimes Act 1961 and the Contraception, Sterilisation and Abortion Act 1977, under the condition that a woman seeking an abortion must receive consent from two specially-appointed doctors.

The changes suggested by the Law Commission would remove the current grounds for abortion in the Crimes Act, remove the requirement that abortions be authorised by two specially-appointed doctors, and would remove offences in the Crimes Act related to abortion. But the key changes as suggested by the Law Commission would be for women to be able to access abortion services directly (instead of via referral), and removing restrictions on facilities and individuals who could perform abortions, such that these would now be provided by local Health Authorities.

The Law Commission briefing paper also provides a series of three possible alternative approaches for abortion law. In “Option A”, the decision to have an abortion would be between a woman and her medical practitioner. In “Option B”, there would be a statutory test, such that the medical practitioner would have to certify that an abortion was appropriate, given “the woman’s physical and mental health and wellbeing”. “Option C” is similar, but the statutory test would only come into play at week 22 of the pregnancy.

A question arises here: what scientific evidence is there to inform us of what option is most appropriate? A series of papers written on outcomes associated with abortion, using data from a 40-year longitudinal study of New Zealanders, may help to address this issue.

The Christchurch Health and Development Study 

The Christchurch Health and Development Study (CHDS) is a study of 1265 individuals (630 females) born in Christchurch in mid-1977 (2). The Study has followed the life course of these individuals from birth to age 40, and as a part of this examination, has studied the pregnancy and parenthood history of these cohort members.

The issue of abortion has been examined in several CHDS publications (3-6). The primary aim of these analyses were to examine the extent to which abortion was associated with an increased risk of mental health disorders (including depression, anxiety, and substance use disorders), and whether these associations could be explained by other factors occurring over the life course of women in the cohort.

Across these studies, there was evidence that exposure to elective abortion was associated with a small increase in the risk of mental disorders, even after controlling for prior mental health and other social and individual factors (3, 4). Women who had reported having an abortion had a 30% greater risk of experiencing mental health disorders, as compared with women who had not had an abortion. These findings suggest that having an abortion increased the risk of mental health disorders, but the size of this effect was relatively small, and certainly no greater than the risks posed by other stressful life experiences.

Significantly, however, a further analysis of the cohort was undertaken in which we examined reactions to abortion (5). This analysis revealed that women who reported more adverse reactions to having had an abortion accounted for the majority of mental health disorders following abortion. This finding indicated that the adverse mental health effects of abortion are likely to occur in women who are conflicted or upset about undertaking the procedure, underscoring the need for effective counselling for women both prior to, and following the abortion procedure.

Two other CHDS papers examining abortion are also worth noting. The first was an analysis that showed that having an abortion resulted in allowing young women to complete their educational qualifications, as compared with women who had had pregnancies come to term (3). These findings suggest that certain aspects of women’s wellbeing, in this case educational attainment (and, by extension, employment prospects), would be compromised if women were required to carry all pregnancies to term.

The second additional paper of interest was a review of the literature on the mental health effects of abortion, with the aim of addressing whether there was any evidence of mental health benefit following abortion (6). The review concluded that there was no evidence of improvement in mental health outcomes following abortion.

What do these findings mean for the law as it stands, and the Law Commision recommendations?

The findings of the review paper noted above highlight a major flaw in the current legislative framework for abortion. Women are currently granted abortions on the grounds that not having an abortion would harm their physical and mental health. Yet, we have shown that there is no evidence for mental health benefits following abortion. It is clear that the mental health provision of the Acts has no foundation, and because of this, it is imperative that these should be changed.

The CHDS findings noted above also have implications for changes to abortion law as mooted by the Law Commission. The statutory requirements of “Option B” and “Option C” are worded in a way that have some unfortunate similarities to the current laws, such that the medical practitioner who certifies that abortion is appropriate can use the same faulty mental health reasoning that is used currently. It would be more appropriate if the language for these options were altered such that the statutory test could be applied taking into consideration women’s “health and wellbeing”, which would remove the explicit mention of mental health benefit (for which there is no evidence), but also include other aspects of wellbeing (such as being able to maintain one’s educational progress).

However, if there are no changes to be made to the language describing each of the three options, the Law Commission will not have dealt with the faulty rationale employed in the current Acts to allow abortions. Because of this, at the present moment in time, the available evidence suggests that the only viable option of the three proposed by the Law Commission is “Option A”, in which abortions are granted upon request, without a statutory test.


It is clear that it is well past time for reform of abortion laws in New Zealand, and the Law Commission briefing paper is a positive step in this direction. However, it is also clear that the Law Commission’s options are worded in such a way that retains the faulty reasoning inherent in the current Acts, and should be changed to be more closely aligned with New Zealand-based scientific evidence on abortion.


  1. New Zealand Law Commission. Alternative approaches to abortion law. Wellington: New Zealand Law Commission, 2018.
  2. Fergusson DM, Horwood LJ. The Christchurch Health and Development Study. In: Joyce P, Nicholls G, Thomas K, Wilkinson T, editors. The Christchurch Experience: 40 Years of Research and Teaching. Christchurch: University of Otago; 2013. p. 79-87.
  3. Fergusson DM, Boden JM, Horwood LJ. Abortion among young women and subsequent life outcomes. Perspect Sex Reprod Health. 2007;39(1):6-12.
  4. Fergusson DM, Horwood LJ, Boden JM. Abortion and mental health disorders: Evidence from a 30 year longitudinal study. Br J Psychiatry. 2008;193:444-51.
  5. Fergusson DM, Horwood LJ, Boden JM. Reactions to abortion and subsequent mental health. Br J Psychiatry. 2009;195:420-6.
  6. Fergusson DM, Horwood LJ, Boden JM. Does abortion reduce the mental health risks of unwanted or unintended pregnancy? A re-appraisal of the evidence. Aust N Z J Psychiatry. 2013;47(9):819-27.

Joseph M. Boden is an Associate Professor in the Department of Psychological Medicine at the University of Otago, Christchurch, and the Deputy Director of the Christchurch Health and Development Study.

Disclaimer: The ideas expressed in this article reflect the author’s views and not necessarily the views of The Big Q. 

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