Endocrine Abstracts

Background: Postpartum depression (PPD) is a common mental health disorder with a major impact on maternal health and wellbeing and offspring development. Thyroperoxidase antibody (TPOAb) positivity is a major risk factor for postpartum thyroiditis and via this link, it is hypothesized that TPOAb positivity is a risk factor for PPD. However, the results of currently available single center studies are heterogeneous and affected by major study limitations.

Objective: To examine the association of TPOAb and thyroid function with the risk of PPD.

Methods: In the Generation R Study, a population-based prospective birth cohort in Rotterdam, The Netherlands, we measured TSH, FT4, and TPOAb in blood samples collected between 8-18 weeks of pregnancy. Postpartum depressive symptoms were assessed with the Edinburgh Postpartum Depression Scale (EPDS) at 2 months postpartum and with the Brief Symptom Inventory (BSI) at 2, 6, and 36 months postpartum. In addition, we performed a systematic review of literature assessing the association of thyroid function and/or TPOAb positivity with risk of PPD and an aggregate data meta-analysis on included studies to generate a pooled risk estimate.

Results: There was no association of TSH or FT4 levels with the risk of postpartum depression (log_TSH OR:0.79, 95%CI 0.56-1.13, P=0.20; fT4 OR:1.02, 95%CI 0.96-1.08, P=0.57) in Generation R study. There was also no association of TPOAb positivity with PPD (OR:0.79, 95%CI 0.45-1.31, P=0.39). Additional analyses assessed an impaired thyroidal response to hCG stimulation and defined the combined effects of a high hCG with either a high TSH or low FT4 as an alternative marker of TPOAb positivity. We identified that an impaired thyroidal response to hCG stimulation was associated with a lower risk of PPD (P for interaction TSH=0.04 and FT4=0.06). In our systematic review, two out of 1219 identified articles were included and they were both eligible for a meta-analysis. The risk of PPD (pooled OR) for TPOAb positivity was 1.20 (95%CI 0.46-3.16).

Conclusions: Our original study is by far the largest study on this topic showing that neither TPOAb positivity nor TSH or FT4 were associated with PPD. Our systematic review revealed high heterogeneity and suboptimal methodological quality in the current literature, but overall does not support a link with PPD. Although TPOAb-positive women should be monitored for postpartum thyroiditis, there does not seem to be an indication to screen for postpartum depression. Further research should focus on other factors potentially involved in the etiology of PPD.