Abstract
Background
Since 2017, there have been three shortages of combined oral contraceptives (COCs) in Aotearoa New Zealand (Aotearoa/NZ) that resulted in reduced supply to users. COCs are the most commonly used hormonal contraceptive in Aotearoa/NZ. Usually, up to a six months’ supply of COCs can be dispensed from pharmacies at a time. During shortages this was reduced to one month (21 days of active medication) for affected COCs while stocks were available. During the most severe of these shortages no supplies of norethisterone-containing COCs were available for several months in 2020-2021. Little is known about COC use in Aotearoa/NZ, and the effects of transient shortages of COCs have not been described.
Shortages have the potential to increase contraceptive burden for users, as they may have to return to the pharmacy more frequently or source alternative methods of contraception. Shortages may therefore logically create increased risk for gaps in COC cover, discontinuation, and unintended pregnancy. This thesis primarily focuses on the early 2019 shortage of Levlen ED (levonorgestrel 150 mcg + ethinyloestradiol 30 mcg), the most commonly used formulation of COC in Aotearoa/NZ.
Aims
The aim of this thesis was to describe key aspects of the utilisation of COCs in Aotearoa/NZ (population and sub-group rates, geographic distribution, COC type, pregnancy rate) and subsequently identify the impacts of shortages on users.
Methods
This mixed-methods thesis used the Integrated Data Infrastructure to identify population-level rates of government-subsidised COC use, any population sub-groups that are more or less likely to use these COCs, the brands and formulations used, and pregnancy rates amongst users. It was then used to explore whether a shortage of Levlen ED in early 2019 was associated with increased rates of gaps in COC supply, discontinuation, non-adherence, non-equivalent brand switching, and pregnancy. A qualitative study was used to explore users’ personal experiences during COC shortages.
Findings
In 2018, government-subsidised COCs were used by 14.3% of reproductive-aged females. There was significant variation in rate of use by ethnicity, neighbourhood deprivation, and rurality, with European/Other individuals and those from the least deprived and major urban areas having significantly higher rates of use. There was also significant regional variation in rate of COC use. While Levlen ED was used by 54.8% of COC users in 2018, anti-androgenic COCs were used by 20.9%. Anti-androgenic COCs were less used by Māori and Pacific Peoples, as well as those living in more deprived and more rural areas. In 2019, there were 3.5 pregnancies per 100 person-years of COC use.
There were small but significant increased risks of gaps in COC supply and discontinuation amongst Levlen ED users in early 2019, compared to users of other COCs. New or restarting and Māori users appeared to have been more vulnerable to these effects. There was no statistically significant association for Levlen ED use and pregnancy rates over this time period, however the effect point estimate (adjusted risk ratio 1.14, 95% confidence interval 0.98-1.33) indicated there may have been an impact. The qualitative findings indicate COC shortages had profound impacts on some users, with increased contraceptive burden. Other adverse experiences ranged from loss of menstrual cycle control to mental health consequences.
Conclusions
There may be disparities in access to or quality of contraceptive services provided. This urgently warrants further research, as current contraceptive services may not be meeting the needs of some groups in Aotearoa/NZ. The funding of stat (all-at-once) dispensing for 12-month supplies of COCs is warranted. Findings also identified that polycystic ovarian syndrome may be being under-diagnosed or under-treated in groups with lower anti-androgenic COC use. There was convincing evidence of shortages having had an impact on users, although further exploration into other COC shortages is warranted. While promoting long-acting reversible contraceptive methods may seem a logical response to COC shortages and the difficulties users may face, such promotion may actually curb reproductive choices and freedoms. Instead, individuals desiring contraception should be supported to use the method/s they prefer. This means future COC shortages need to be well-managed to minimise and mitigate any ramifications for users. This could include partnership with affected groups to explore impact minimisation strategies for future shortages.