Efficacy of contraceptive methods: a review of the literature.

OBJECTIVES

To provide a comprehensive and objective summary of contraceptive failure rates for a variety of methods based on a systematic review of the literature.

METHODS

Medline and Embase were searched using the Ovid interface from January 1990 to February 2008, as well as the reference lists of published articles, to identify studies reporting contraceptive efficacy as a Pearl Index or life-table estimate. Reports that recruited less than 400 subjects per study group and those covering less than six cycles/six months were excluded. In addition, unlicensed products or those not internationally available, emergency contraception, and vasectomy studies were excluded.

RESULTS

Information was identified and extracted from 139 studies. One-year Pearl Indices reported for short-acting user-dependent hormonal methods were generally less than 2.5. Gross life-table rates for long-acting hormonal methods (implants and the levonorgestrel releasing-intrauterine system [LNG-IUS]) generally ranged between 0-0.6 per 100 at one year, but wider ranges (0.1-1.5 per 100) were observed for the copper intrauterine devices (0.1-1.4 per 100 for Cu-UIDs with surface area ≥ 300 mm2 and 0.6-1.5 per 100 for those with surface area < 300 mm2). Barrier and natural methods were the least effective.

CONCLUSIONS

Our review broadly confirms the hierarchy of contraceptive effectiveness in descending order as: (1) female sterilisation, long-acting hormonal contraceptives (LNG-IUS and implants); (2) Cu-IUDs with ≥ 300 mm2 surface area; (3) Cu-IUDs with < 300 mm2 surface area and short-acting hormonal contraceptives ( injectables, oral contraceptives, the patch and vaginal rings), (4) barrier methods and natural methods.