Validity and reliability of maternal recall of pregnancy history and service use among signing Deaf women: a cross-sectional descriptive study from South Africa

INTRODUCTION: There is little credible quantitative data on pregnancy histories and outcomes for disabled women in low-income and middle-income countries. The purpose of this study, based in Cape Town, South Africa, was to test the reliability and validity of maternal recall of pregnancy history and service use among a sample of Deaf women who use South African Sign Language (SASL). METHODS: We interviewed 42 signing Deaf women of childbearing age (18–49 years) in SASL using a structured questionnaire in July 2016. To assess reliability, seven participants (16% of the sample) were reinterviewed by different interviewers under the same conditions after 10–30 min. For the analysis we used (1) Cohen’s kappa, an inter-rater statistical method, and (2) overall percentage agreement. Validity was explored by comparing the participants’ pregnancy history to the Western Cape Provincial Health Data Centre (PHDC) database. RESULTS: The reliability results showed that out of 19 questions 14 demonstrated substantial to perfect agreement kappa scores (kappa between 0.61 and 1) and 5 had the lowest kappa agreement scores (kappa <0.61). With respect to percentage agreement, participants provided identical responses in 87% cases. Overall, women provided more reliable responses to pregnancy outcomes compared with demographic information. Validity results showed that 29 out of 35 Deaf women provided survey responses that matched or nearly matched (83% agreement) the PHDC database for birth history and delivery location. CONCLUSION: This study suggests that for this sample of signing Deaf women recall of pregnancy history and service use is reliable and valid. Extending this approach to other similar populations will require further research, but it is important that methods to access hard-to-reach disabled populations are developed so that health system responsiveness to marginal populations can be based on robust evidence.