Association of gestational thyroid function and thyroid peroxidase antibody positivity with postpartum depression: a prospective cohort study and systematic literature review with meta-analysis

Importance: Postpartum depression (PPD) has a major impact on maternal and offspring well-being, with multiple possible risk factors: Studies on the association of thyroid peroxidase antibody (TPOAb) positivity and thyroid function with PPD provide heterogeneous results. Objective: To study the association of thyroid function and TPOAb positivity with PPD. Design: We assessed the association of TPOAb and thyroid function with PPD in a population-based prospective cohort study and performed a systematic literature review and meta-analysis. Methods: We measured thyroid stimulating hormone (TSH), free thyroxine (FT4), and TPOAb between 9- and 17-week gestation. Postpartum depression was assessed with Edinburgh Postpartum Depression Scale at 2-month postpartum and Brief Symptom Inventory at 2-, 6-, and 36-month postpartum. Additionally, we performed a systematic literature review and meta-analysis assessing this association. Results: In the present study, there was no association of thyroid function with PPD (TSH: odds ratio [OR] 0.83, 95% CI 0.58-1.19, P = .32; FT4: OR 0.99, 95% CI 0.95-1.05, P = .86) or TPOAb positivity with PPD (OR 0.79, 95% CI 0.47-1.33, P = .37). An impaired thyroidal response to human chorionic gonadotropin (hCG), a surrogate marker for TPOAb positivity, was associated with a lower risk of PPD (P for interaction TSH = 0.04; FT4 = 0.06). Our systematic review and meta-analysis included 3 articles that were combined with the present study. There was no statistically significant association of TPOAb positivity with PPD (OR 1.93, 95% CI 0.91-4.10, P = .08), but the results were heterogeneous (I2 = 79%). Conclusions and relevance: There was no significant association of TPOAb positivity, TSH, or FT4 with PPD. Our systematic review and meta-analysis revealed high heterogeneity of the current literature. Although TPOAb-positive women should be monitored for postpartum thyroiditis, our findings do not support routinely screening for PPD.