Social gradients in surgical sterilization rates: opposing patterns for males and females

The purpose of this study was to analyze population-based rates of surgical sterilization by sex, income, age group, and location of residence (urban, rural, or remote) among a universally insured population.

The study included all 1.2 million residents of Manitoba. Data from comprehensive hospital and medical visit records were used to calculate rates of vasectomy and tubal ligation among the population aged 20 to 55 years. Analyses were carried out with generalized linear modelling, using administrative data housed at the Manitoba Centre for Health Policy.

There were significant income-related gradients in sterilization rates for both sexes (P < 0.001), but the trends were in opposite directions for males and females. Tubal ligation rates were highest in low-income areas, and decreased with income, whereas vasectomy rates were lowest in low-income areas and increased with income. Rates also varied considerably by age and area of residence (urban, rural, or remote).

These results are potentially worrying because tubal ligation is more invasive, associated with higher risks, and more costly than vasectomy. It would therefore be expected to be less common than vasectomy among all groups, not just those in higher income areas. The results contribute unique population-based procedure rates, which are not subject to biases that can affect survey-based studies. The findings may reflect underlying differences across income groups in decision-making regarding reproductive health issues.