Lo. Retrospective observational cohort study. This included ♀ with a history of BD or postpartum psychosis, used Li+ during pregnancy, and at least one Li+ serum level during pregnancy was available. Linear and logistic regression models used to investigate the association between weighted average Li+ level and pregnancy duration, birth weight percentiles, preterm birth, and LGA. Subsequent exploratory analyses investigated the role of TSH and T4 as mediators of associations. The gene discussed is CD4; the disease is psychotic disorder.