Association Between Women's Use of Long-Acting Reversible Contraception and Declining Abortion Rates in New Zealand.

Background

To investigate the hypothesis that increased uptake of long-acting reversible contraception (LARC) by women played a role in the declining abortion rates observed in New Zealand between 2008 and 2014. Materials and

Methods

This quantitative ecological study analyzed routinely collected national data pertaining to abortion numbers, contraceptive prescriptions, and census population estimates for the period 2004-2014. Annual prescription and prevalence rates (per 1000 women) were calculated for short- and long-acting methods to investigate changes over time. Poisson's regression was used to (1) test whether the abortion rate changed by year; (2) whether 2010 (when the contraceptive implant became subsidized) was a significant point of change; and (3) test the relationship between declining abortions and patterns of contraceptive use.

Results

Estimated LARC prevalence increased from 2009 to 2014, with a corresponding decrease observed in prescription of short-acting methods. The declining abortion rate accelerated each year from 2008 to 2014 (with a faster decline from 2010 to 2014), but 2010 was not a significant point of change. Three factors had statistically significant associations with declining abortion rates (p < 0.01): year (acting as a surrogate for all social changes), women's use of the levonorgestrel (LNG)-implant, and the combined model: use of the LNG-implant and copper intrauterine device (CuIUD) had the best fit (using Akaike's Information Criterion), indicating that this variable explained more of the year-to-year variability in abortion rates.

Conclusions

The shift toward women's increased use of the two publically funded LARC methods (LNG-implants and CuIUD) was significantly associated with the declining abortion rates in New Zealand.