Unwanted pregnancy and contraceptive knowledge: Identifying vulnerable groups from a randomized controlled trial of educational interventions

Abstract

Objectives. The aim of this study was to identify predictors of contraceptive pill knowledge and their relationship to educational interventions. Methods. A total of 636 women attending for a follow-up appointment for repeat prescription of the combined oral contraceptive pill with a GP or practice nurse were randomized to receive leaflets (simple summary leaflet or FPA leaflet), advice or neither. Sociodemographic details and contraceptive knowledge were determined using a validated contraceptive knowledge questionnaire sent after 3 months by post. The main outcomes were sociodemographic, contraceptive, attitudinal and educational predictors of knowledge. Results. A total of 522 (82%) had complete questionnaires. After controlling for educational intervention and other confounding variables, independent predictors of knowledge were further education (adjusted odds ratio 2.98, 95% confidence interval 1.78-4.99); number of years on the pill (0-5, 6-10, > 10 years) 1.0, 0.56 (0.33-0.95) and 0.34 (0.19-0.59), respectively; past emergency contraception (1.87, 1.18-2.97); and importance attached to not falling pregnant (1.83, 1.02-3.29). These predictors are less powerful than the impact of most educational interventions (range of odds ratios for interventions: 1.85-6.81), and there was no evidence of a separate effect of educational intervention in any subgroup, except that leaflets have a larger effect in women who have needed emergency contraception in the past (no past use or simple summary and FPA leaflets, 1.74 and 0.90, respectively; with past use, 3.47 and 3.83; interaction term chi-square 6.92, P = 0.03). Conclusion. Educational interventions are as important as sociodemographic features in determining knowledge. With limited time for full educational interventions in practice, priorities for intervention should be women who have used emergency contraception in the past - who will benefit most - and those on the pill for >5 years or with no further education who are at highest risk due to poor knowledge.