Objectives: The overall aim of this thesis was to contribute to the development of clinical interventions to prevent or reduce maternal symptoms of childbirth-related post-traumatic stress disorder (CB-PTSD). To do so, it relied on the literature on memory (re)consolidation, which corresponds to a set of processes potentially involved in the development and maintenance of CB-PTSD. The ambition of this thesis was to translate the research on memory (re)consolidation, mainly based on laboratory studies, into applied clinical proposals. Several avenues were explored: 1. Identifying factors that may modulate the consolidation of the traumatic birth memory (TBM) such as prenatal insomnia symptoms (Study 1), administration of nitrous oxide gas (N2O) or morphine during childbirth (Study 2), and CB-PTSD symptoms; and 2. Testing the effectiveness of brief visuospatial task-based interventions, which are assumed to interfere with the (re)consolidation of the TBM, in preventing (Study 3) or reducing (Study 4) CB-PTSD symptoms.
Methods: Studies 1 (n = 1,610) and 2 (n = 2,070) were based on a prospective population-based cohort study (secondary data analyses), following women from pregnancy to eight weeks postpartum. Variables were measured via self-report questionnaires and patients' medical records. CB-PTSD was assessed at eight weeks postpartum. Study 3 (n = 144) is an ongoing multicentre, double-blind, randomised controlled trial (thus, results are not available yet). The intervention tested is delivered within six hours postpartum, and its effectiveness is primarily measured by a childbirth-related intrusive traumatic memories (ITMs) diary over the first week postpartum and an assessment of CB-PTSD symptoms at six weeks postpartum. Finally, Study 4 (n = 18) was a single-group pre-post study. The benefits of the intervention were measured with an ITMs diary over two weeks before and six weeks after the intervention, and CB-PTSD symptoms were measured with a self-report questionnaire, five days before and one month after the intervention.
Results: In Study 1, prenatal insomnia symptoms were associated with CB-PTSD symptom severity, and this relationship was fully mediated by a negative subjective birth experience, as well as by postnatal insomnia symptoms. In Study 2, N2O administration during childbirth predicted less severe CB-PTSD symptoms. This was marginally the case with morphine. However, both analgesics predicted more CB-PTSD symptoms when combined with very severe pain during childbirth. Finally, participants in Study 4 reported a large reduction in their number of ITMs, and it persisted for up to six weeks post-intervention. Their CB-PTSD symptoms were also greatly reduced.
Clinical implications: The results of this thesis suggest a number of avenues for preventing or reducing CB-PTSD symptoms through brief, simple, cost-effective, and innovative interventions. These could potentially be implemented throughout the perinatal period and notably pave the way for pharmacological (Study 2) or psychological (Studies 1 and 3) strategies for CB-PTSD prevention, for which there is currently no evidence-based intervention.