Abstract
The objective of this study was to determine the relationship between postpartum zinc status and postnatal depression, and to evaluate the zinc taste test as a screening test for postpartum zinc deficiency. This case-controlled study was undertaken in a postnatal ward and general practice. Ten women in the last trimester of pregnancy with no previous evidence of postnatal depression were selected from a general practice antenatal clinic and 10 non-pregnant matched controls were selected from practice records. the mood of all subjects was assessed using the Edinburgh postnatal depression scale and a modified version of the same scale was used for controls. Zinc status was evaluated by measuring serum zinc and leucocyte zinc and use of the zinc taste test. Mood and zinc status were evaluated immediately after birth and 10–14 days later in the test cases and once for the controls. There was an overall trend for zinc status to be low immediately after birth, with a mean serum zinc of 7.8 μmol l−1 leucocyte zinc 83 ng mg−1 and zinc test score 1.1, and depression score high with a mean of 9. 7. Measurements for both zinc status and depression tended to return to normal after 2 weeks. There was a negative though not statistically signifcant correlation between serum zinc and postnatal depression score (r=-0.46) and a positive, non-signifcant correlation between serum zinc and the zinc taste tesr (r= + 0.42), but no correlation was seen between leucocyte zinc and any other parameter. One test case developed clinical postnatal depression. Transient zinc deficiency may be a factor in the early stages of postnatal depression, but accurate measurement of zinc status is difficult. the zinc taste test needs to be improved in accuracy and range to be a useful research or clinical tool.