Factors Associated with Non-Response in a Population-Based Pregnancy Cohort

Abstract

The objective of this study was to determine if selection bias was present in an observation cohort study during pregnancy called the Vulvar Pain across Pregnancy Study (VPREG). The investigators sought to determine whether demographic or co-morbid characteristics varied between women who agreed to be in the cohort study (responders) and those who did not (non-responders). The VPREG cohort enrolled pregnant women who were in their first or early second trimester. Nearly half of the women had a history of chronic vulvar pain while the others had no history. Responders and non-responders were compared to each other on age, marital status, education, and co-morbid conditions. Responders (n=86) and non-responders (n=279) were similar in all characteristics except education and marital status. Responders had attained a higher level of education and were more likely to be married. Women who were lost to follow-up were also compared based on these characteristics. The main differences found in women who were lost to follow-up were in the co-morbid conditions. These women had a greater incidence of depression and anxiety.