Tryptophan, cortisol and puerperal mood

Area of Science:

• Reproductive endocrinology
• Neurochemistry
• Perinatal mental health

Background:

• Postpartum mood disturbances, including the 'blues', affect a significant number of women.
• Biochemical factors, such as hormones and neurotransmitter precursors, are implicated in mood regulation.
• Understanding the interplay between physiological changes and mood during the perinatal period is crucial.

Purpose of the Study:

• To investigate the relationship between plasma cortisol, tryptophan levels, and the incidence of postpartum 'blues'.
• To explore potential seasonal variations in these biochemical markers and mood states.
• To identify biochemical predictors of postpartum depression and related mood complaints.

Main Methods:

• Longitudinal study of 71 women from 36 weeks gestation to 6 weeks postpartum.
• Measurement of plasma cortisol, free tryptophan, and total tryptophan at 8 time points.
• Assessment of affective state using rating scales and clinical interviews; identification of postpartum 'blues'.

Main Results:

• Seasonal variations were observed in postpartum 'blues' incidence, cortisol, and free tryptophan levels.
• Elevated cortisol at 38 weeks gestation correlated with puerperal depression, independent of season.
• Absence of the typical early postpartum rise in total tryptophan was linked to increased risk of postpartum 'blues' and subsequent depression.

Conclusions:

• Plasma cortisol and tryptophan levels exhibit dynamic changes during the perinatal period, influenced by season and mood.
• An atypical total tryptophan surge postpartum may indicate a susceptibility to mood disorders.
• These findings suggest a potential role for tryptophan metabolism disturbances in the pathophysiology of postpartum depression.