The epidemiology of hospitalized postpartum depression in New York State, 1995-2004.

Purpose: The purpose of this study is to describe the patterns of hospitalization for depression in the year after delivery in relation to social, demographic, and behavioral characteristics.

Methods: Data on births were linked to hospitalizations for depression over the subsequent year to describe the frequency and patterns of hospitalized postpartum depression among 2,355,886 deliveries in New York State from 1995 to 2004. We identified "definite postpartum depression" based on International Classification of Diseases (ICD) codes indicative of "mental disorders specific to pregnancy," and "possible postpartum depression" by ICD codes for hospitalization with any depressive disorders.

Results: In New York State, we identified 1363 women (5.8 per 10,000) who were hospitalized with definite postpartum depression, and 6041 women (25.6 per 10,000) with possible postpartum depression, with lower risks in the New York City area. Postpartum depression was more common in later years and among mothers who were older, Black, smokers, lacking private insurance, and with multiple gestations, and was rarer among Asians. For possible postpartum depression, socioeconomic gradients were enhanced.

Conclusions: Risk of hospitalized postpartum depression is strongly associated with socioeconomic deprivation and varies markedly by ethnicity, with direct implications for screening and health services, also providing suggestions for etiologic studies.