Development of a Pre- and Postnatal Bonding Scale (PPBS)

Objective: Bonding is a major topic in the field of developmental psychology, due to its importance in adequate childhood development. Studies investigating the relationship between pre- and postnatal bonding show moderate correlations. However, an important limitation is that no similar instruments were used to measure bonding pre- and post-natally. In the current study, a user-friendly questionnaire has been developed to assess maternal bonding during pregnancy and postpartum. Psychometric properties were also investigated.

Methods: In a large unselected sample of 1050 pregnant women, 14 positive items, based on the literature, were used to construct a pre- and postnatal bonding scale (PPBS) questionnaire. The sample was randomly split into two equal sub-samples: group I was used for reliability and Exploratory Factor Analysis; group II for Confirmatory Factor Analysis (CFA). The bonding scale was assessed at 32 weeks pregnancy and at eight and 12 months postpartum. The Edinburgh Depression Scale (EDS) and the subscale Partner Involvement of the Tilburg Pregnancy Distress Scale (TPDS) were used to assess concurrent validity.

Results: After CFA, a five-item bonding scale remained with excellent model fit (CFI: 0.97, TLI: 0.97, NFI: 0.98; RMSEA: 0.06 lower bound 0.03. Cronbach’s alpha’s at 32 weeks gestation and at eight and 12 months' postpartum were: 0.87, 0.80 and 0.79, respectively. Test-retest correlations of the PPBS at 32 weeks gestation and at eight and 12 months postpartum were high: 0.42 and 0.41 and 0.67 between eight and 12 months post-partum, respectively. At 32 weeks gestation, the PPBS correlated significantly with partner support (TPDS): 0.38 and depression (EDS): -0.24. Similar correlations with depression were found at eight and 12 months post-partum.

Conclusion: The five-item PPBS seems to be a user-friendly self-rating scale with good psychometric properties and concurrent validity, both pre- and post-natally.