Hasan R, Jonsson Funk ML, Herring AH, Olshan AF, Hartmann KE, Baird DD. Accuracy of reporting bleeding during pregnancy. Paediatric and Perinatal Epidemiology 2010; 24: 31–34.
Vaginal bleeding during pregnancy has been considered a marker of an at-risk pregnancy, but the accuracy of reported bleeding has not been assessed. We sought to evaluate the agreement in vaginal bleeding reports based on prospective daily diary and retrospective recall at first-trimester interview and to investigate predictors of reporting accuracy. Participants recruited prior to pregnancy for a community-based pregnancy cohort (n = 153) completed web-based daily diaries beginning before pregnancy until the end of the first trimester. A comprehensive first-trimester interview was conducted, and the bleeding data from diary and interview were compared. Kappa statistics were used to quantify agreement. Log-linear models were used to investigate maternal age, prior miscarriage, and current pregnancy outcome as potential predictors of agreement.
We found that bleeding characteristics (number of bleeding episodes, bleeding heaviness, duration and gestational timing) from the diary and interview were reported with high levels of agreement. Kappas ranged from 0.77 to 0.84. Retrospective report of any bleeding had a sensitivity of 0.80 and specificity of 1.0; however, sensitivity was lower when examined within smaller time intervals. Important predictors of agreement were not identified in this analysis, but the sample was small. Overall, the presence of vaginal bleeding, a common and potentially alarming symptom of early pregnancy, may be assessed by interview later in pregnancy with reasonable accuracy.