Identifying gaps in dual protection from sexually transmissible infections and unintended pregnancies among Australian women: An observational study

Dual protection refers to the simultaneous prevention of sexually transmissible infection (STI) and unintended pregnancies. Optimal contraception and STI prevention strategies sometimes fail to align. Methods: Using data from a large nationally representative population-based survey, we analysed the contraception and STI prevention behaviours at the last vaginal intercourse among 2420 heterosexually active women aged 16-34 years who had participated in the Second Australian Study of Health and Relationships, 2012-13. Results: At their last vaginal intercourse, most women (95%) used contraception and half (49%) used condoms, either as a sole multipurpose method or in conjunction with another type of contraception. Condom use was highest (72%) among women whose most recent partner was a casual or occasional partner, followed by women with a regular partner (59%) and women with a cohabiting regular partner (40%). One-third of the women (34%) used condoms as a sole method, and 14% used oral contraceptives together with a condom. Few women used implants or intrauterine devices (8%) and, among them, very few women also used condoms (<1%). Among the women who used a condom at their last vaginal intercourse, 49% reported both the correct use for STI prevention and consistent condom use during the previous 6 months. Among women using condoms, correct and consistent use was also highest among women whose most recent partner was a casual or occasional partner (76%). Conclusions: Although almost all women used contraception and half used dual protection, few benefited from the protective effects of using condoms together with highly effective contraception.