Chanel Brocherie¹, Alex C. Varghese¹², Kanna Jayaprakasan³, Ashleigh Storr¹⁴

¹²⁴ Fertility Associates, Auckland, New Zealand
³ Nuffield Health Derby Hospital, Derby, United Kingdom

Equitable access to fertility treatment and equitable reproductive outcomes are important priorities within New Zealand's increasingly diverse population. While disparities in reproductive health outcomes between ethnic groups have been documented internationally, relatively little is known about whether ethnicity independently influences outcomes following in vitro fertilisation (IVF) within the New Zealand healthcare context. Understanding such differences is particularly relevant to ensuring that fertility services appropriately meet the needs of Māori, Pacific peoples, and other ethnic communities.

This multicentre retrospective cohort study analysed routinely collected clinical data from five tertiary fertility clinics across New Zealand between January 2016 and June 2024. The study included 7,547 women undergoing a first embryo transfer and 10,244 oocyte pick-up (OPU) cycles for cumulative outcome analyses. Ethnicity was self-reported and categorised into ten groups, with European women serving as the reference population. Multivariable logistic regression was used to assess associations between ethnicity and IVF outcomes after adjustment for established prognostic factors, including age at OPU, body mass index (BMI), and anti-Müllerian hormone (AMH). Outcomes examined included live birth following first embryo transfer, cumulative live birth per OPU cycle, biochemical pregnancy, cumulative pregnancy, and biochemical pregnancy loss.

Marked differences in outcomes were observed between ethnic groups. European women had the highest live birth rate following first embryo transfer (40.2%), while Pacific women had the lowest unadjusted rate (28.4%). After adjustment for age, BMI, and AMH, Māori women (adjusted odds ratio [aOR] 0.68, 95% confidence interval [CI] 0.55-0.83), South Asian women (aOR 0.56, 95% CI 0.46-0.69), Other Asian women (aOR 0.68, 95% CI 0.50-0.91), Middle Eastern women (aOR 0.64, 95% CI 0.42-0.98), and women from other ethnic groups (aOR 0.68, 95% CI 0.55-0.83) had significantly lower odds of live birth following first embryo transfer than European women. Lower cumulative live birth rates remained evident for Māori, South Asian, and Other Asian women after adjustment. Increasing maternal age was the strongest adverse predictor of live birth, while higher BMI was associated with a modest reduction in cumulative live birth and higher AMH was associated with improved outcomes.

These findings demonstrate significant ethnic variation in IVF outcomes in New Zealand that is not fully explained by age, BMI, or ovarian reserve. Although Pacific women had the lowest unadjusted live birth rates, further work is required to better understand the drivers of observed differences across ethnic communities, including biological, clinical, cultural, socioeconomic, and health-system factors. The findings highlight the importance of ongoing equity-focused research and service development to ensure fertility treatment outcomes are optimised for all New Zealanders.