Primary outcome
The primary outcome was self-reported Psychological well-being at 29–34
weeks of gestation by the five-item World Health Organization Well-being
Index (WHO-5). The WHO-5 measures current, general, subjective
psychological well-being covering the prior two weeks, and consists of
five items, each scored on a Likert scale (from 0 = “none of the time”
to 5 = “all of the time”). Because scales measuring health-related
quality of life are usually translated to a percentage scale from 0
(lowest possible well-being) to 100 (highest possible well-being), the
raw WHO-5 ranging from 0 to 25 were multiplied by a factor of 4. Using a
cut-off score of ≤50 the WHO-5 has a high sensitivity (0.87) and
specificity (0.76) for depression defined according to the DSM- IV
(22).