Background: There has been a proliferation of repeat prenatal ultrasound examinations per pregnancy in many developed countries over the past 20 years, yet few studies have examined the main determinants of the utilization of prenatal ultrasonography.
Objective: The objective of this study was to examine the influence of the type of provider, place of residence and a wide range of socioeconomic and demographic factors on the frequency of prenatal ultrasounds in Canada, while controlling for maternal risk profiles.
Methods: The study utilized the data set of the Maternity Experience Survey (MES) conducted by Statistics Canada in 2006. Using an appropriate count data regression model, the study assessed the influence of a wide range of socioeconomic, demographic, maternal risk factors and types of provider on the number of prenatal ultrasounds. The regression model was further extended by interacting providers with provinces to assess the differential influence of types of provider on the number of ultrasounds both across and within provinces.
Results: The results suggested that, in addition to maternal risk factors, the number of ultrasounds was also influenced by the type of healthcare provider and geographic regions. Obstetricians/gynaecologists were likely to recommend more ultrasounds than family physicians, midwives and nurse practitioners. Similarly, birthing women who received their care in Ontario were likely to have more ultrasounds than women who received their prenatal care in other provinces/territories. Additional analysis involving interactions between providers and provinces suggested that the inter-provincial variations were particularly more pronounced for family physicians/general practitioners than for obstetricians/gynaecologists. Similarly, the results for intra-provincial variations suggested that compared with obstetricians/gynaecologists, family physicians/GPs ordered fewer ultrasound examinations in Prince Edward Island, British Columbia, Nova Scotia, Alberta and Newfoundland.
Conclusion: After controlling for a number of socioeconomic and demographic factors, as well as maternal risk factors, it was found that the type of provider and the province of prenatal care were statistically significant determinants of the frequency of use of ultrasounds. Additional analysis involving interactions between providers and provinces indicated wide intra- and inter-provincial variations in the use of prenatal ultrasounds. New policy measures are needed at the provincial and federal government levels to achieve more appropriate use of prenatal ultrasonography.