PURPOSE: A previous diagnosis of depression is a strong predictor for perinatal depression, apart from other mental disorders, stress, and atopies. It is less clear which factors interfere if perinatal depression occurs as a first depression episode (fePND). METHODS: We examined the associations with atopies and related blood parameters using data of CoLaus|PsyCoLaus. RESULTS: Newly occurring depression during the perinatal period but not recurrent depression was associated with a lifetime diagnosis of allergies and asthma together with persistently increased levels of basophils and eosinophils. CONCLUSION: The results imply that immune function may play a relevant role in the risk of a fePND. If confirmed and detailed, these findings could serve as the basis for designing preliminary prevention strategies by observing eosinophil and basophil levels as well as symptoms of atopic diseases before/during pregnancy.