Retention rates and potential predictors in a longitudinal randomized control trial to prevent postpartum depression

SUMMARYPerinatal depression is increasingly recognized as a significant publicmental health problem; consequently, there is a major interest indeveloping strategies to prevent postpartum depression that may helpreduce its detrimental consequences. However, the unique experiencesassociated with the perinatal period make it more difficult to recruitparticipants at this stage and to retain them over time when assessingprevention interventions. The aim of the study is to examine retentionrates and predictors of retention in a longitudinal, randomizedcontrolled trial (RCT) to prevent postnatal depression.MethodParticipants: Pregnant women (N=377) at risk of depression wererandomized to intervention or usual care condition and assessedduring pregnancy and at 6 weeks and 4-6 months postpartum.Intervention: The intervention was designed by modifying apreviously evaluated one and includes information on normalpregnancy and the postpartum period, from psychoanalytic and riskfactors perspectives. It attempts to reduce depression levels byincreasing positive thinking and pleasant activities, improving self-esteem, increasing self-care, learning skills to strengthen socialsupport, and exploring unrealistic expectations about pregnancy andmotherhood. It is delivered in eight two-hour weekly group sessionsduring pregnancy.Measures: Depressive symptoms were measured using the secondedition of the Beck Depression Inventory (BDI-II); anxiety symptomswith the corresponding subscale of the Hopkins Symptoms Checklist(SCL-90) and social support with the Social Support Apgar (SSA). Ashort form of 12 items representing potential stressors was used as ameasurement of stressful life events and the Abbreviated Version ofthe Dyadic Adjustment Scale (A-DAS) measured partner relationship.ResultsRetention rates −defined in three ways− were: (1) Total retention(percentage of participants completing the 4-6 month postpartuminterview) was 41.7% (31.2% intervention and 61.4% control); (2)Retention from randomization to (a) completion of initial evaluationand attendance of ≥ 1 intervention sessions was 42.4%; and (b)completion of initial evaluation (control) was 82.2%; and (3) Follow-up retention: (a) intervention participants attending ≥ 1 sessions thatcompleted the intervention as well as the 4-6 months postpartuminterview was 73.5%; and (b) control participants assesses in thisperiod was 66.6%. For those who came to at least one interventionsession 83% completed the intervention.The predictors of total retention were: being single, moreeducated, and poor partner relationship quality . For the interventioncondition, predictors of (a) retention from randomization to attendanceto ≥ 1 sessions were anxiety and stressful life events, and (b) forfollow-up retention was being employed.ConclusionsIn the present study, retention of participants was even lower than whathas been found in similar interventions. However, attendance rates ofthe course, once the participants had attended one session, were verygood. In terms of predictors of retention, women at high risk ofdepression (single, with poor partner quality relationship, more stressfullife events and high anxiety) were more committed to participating inthe study. Consequently, in order to increase retention rates, futureinterventions should target women that present such risk factors.Nevertheless, those with low educational attainment and homemakers,who are a vulnerable group, were difficult to retain and thus remain achallenge in postpartum depression prevention studies. We concludethat rates and predictors of retention differed depending on points ofmeasurement, suggesting different strategies to optimize participation.Key words: Postnatal depression, prevention, retention, psycho-educational interventions.RESUMENLa depresion perinatal cobra cada dia mayor reconocimiento comoun problema importante de salud mental publica; en consecuencia,ha crecido el interes por desarrollar estrategias para prevenir ladepresion posparto, que lleven a evitar sus consecuencias adversas.Sin embargo, las peculiaridades del periodo perinatal dificultan tantoel reclutamiento como la retencion de esta poblacion a lo largo deltiempo, cuando se evaluan intervenciones preventivas. El objetivodel estudio es examinar las tasas de retencion y las variables quepredicen las mismas en un estudio longitudinal aleatorio controlado(EAC) para prevenir la depresion posparto.MetodoParticipantes: Trescientas setenta y siete embarazadas que mostra-ron riesgo de depresion fueron aleatorizadas a grupos de interven-