Contraceptive use among women through their later reproductive years: Findings from an Australian prospective cohort study.

Objective: Examine patterns of contraceptive use and contraceptive transitions over time among an Australian cohort of women through their later reproductive years.

Study Design: Latent Transition Analysis was performed using data on 8,197 women from the Australian Longitudinal Study on Women's Health's 1973-78 cohort to identify distinct patterns of contraceptive use across 2006, 2012 and 2018. Women were excluded from the analysis at time points where they were not at risk of an unintended pregnancy. Latent status membership probabilities, item-response probabilities, transitions probabilities and the effect of predictors on latent status membership were estimated and reported.

Results: Patterns of contraceptive use were relatively consistent over time, particularly for high efficacy contraceptive methods with 71% of women using long-acting reversible contraceptives in 2012 also using long-acting reversible contraceptives in 2018. Multiple contraceptive use was highest in 2006 when women were aged 28-33 years (19.3%) but declined over time to 14.3% in 2018 when women were aged 40-45 years. Overall, contraceptive patterns stabilised as the women moved into their late 30s and early 40s.

Conclusions: Although fertility declines with age, the stability of contraceptive choice and continued use of short-acting contraception among some women suggests that a contraceptive review may be helpful for women during perimenopause so that they are provided with contraceptive options most appropriate to their specific circumstances.