Rates of prenatal screening across health care regions in Ontario, Canada: a retrospective cohort study

Abstract

Background: It is recommended that all pregnant women be offered screening for Down syndrome and open neural tube defects, but emerging prenatal tests that are not publicly insured may compromise access. We evaluated screening rates for publicly insured screening tests across health care regions in the province of Ontario and determined whether maternal, provider or regional characteristics are associated with screening uptake.

Methods: We conducted a population-based retrospective cohort study involving pregnant women in Ontario who were at or beyond 16 weeks' gestation in 2007-2009. We ascertained prenatal screening rates using linked health administrative and prenatal screening datasets. We examined maternal, provider and regional characteristics associated with screening uptake. Rate ratios (RRs) were estimated.

Results: Of the 264 737 women included in the study, 62.2% received prenatal screening; uptake varied considerably by region (range 27.8%-80.3%). A greater proportion of women initiated screening in the first rather than the second trimester (50.0% v. 12.2%). Factors associated with lower screening rates included living in a rural area versus an urban area (adjusted rate ratio 0.64, 95% confidence interval [CI] 0.63-0.66), receiving first-trimester care from a family physician or midwife versus an obstetrician (adjusted rate ratio 0.91, 95% CI 0.90-0.92, and 0.40, 95% CI 0.38-0.43, respectively) and being in a lower income quintile (adjusted RR for lowest v. highest 0.95, 95% CI 0.94-0.96). Being an immigrant or a refugee was associated with higher screening rates.

Interpretation: There were significant maternal, provider and regional differences in the uptake of prenatal screening across the province. With discrepancies expected to increase with the emergence of noninvasive prenatal tests paid for out of pocket by many women, policy efforts to reduce barriers to prenatal screening and optimize its availability are warranted.

Figure 1:

Map of prenatal screening rates across Ontario’s 14 local health regions (1 = Erie St. Clair, 2 = South West, 3 = Waterloo Wellington, 4 = Hamilton Niagara Haldimand Brant, 5 = Central West, 6 = Mississauga Oakville, 7 = Toronto Central, 8 = Central, 9 = Central East, 10 = South East, 11 = Champlain, 12 = North Simcoe Muskoka, 13 = North East, 14 = North West). * = screening centre.

Figure 2:

Screening rates by trimester across Ontario’s 14 health regions (1 = Erie St. Clair, 2 = South West, 3 = Waterloo Wellington, 4 = Hamilton Niagara Haldimand Brant, 5 = Central West, 6 = Mississauga Oakville, 7 = Toronto Central, 8 = Central, 9 = Central East, 10 = South East, 11 = Champlain, 12 = North Simcoe Muskoka, 13 = North East, 14 = North West).