Causal associations of Insomnia and postpartum depression: a two-sample mendelian randomization study

Postpartum depression (PPD), a prevalent social-mental condition, impacts the mother and the newborn and several facets of their lives. It has been suggested that insomnia is related to both the occurrence and progression of PPD. However, because of lingering confounding and bias, it is impossible to determine the cause of this connection using observational analysis. In this study, we evaluate the causal importance of insomnia on postpartum depression using Mendelian randomization (MR).

Utilizing summary data from genome-wide association studies (GWAS), a two-sample MR study was conducted. A GWAS dataset of IEU study of the United Kingdom Biobank phenotypes comprising 462,341 people of European heritage yielded 38 single-nucleotide polymorphisms (SNPs) for insomnia. The PPD data were provided by the FinnGen project and comprised 7604 cases and 59,601 controls. Inverse variance weighting (IVW) was utilized for the primary MR analysis, with weighted median and MR-Egger as sensitivity analyses.

As a result, we found that genetically predicted insomnia was positively associated with postpartum depression. The odds ratios (OR) of PPD were 1.849 (95% (confidence interval) CI 1.011-3.381; p = 0.046).

For the first time, the causative role of sleeplessness for postpartum depression has been extensively evaluated in the current two-sample MR investigation. Our findings show that insomnia and PPD are related causally.