Maternal psychiatric disorders before, during, and after pregnancy: a national cohort study in Sweden.

Maternal mental health is a critical public health issue, yet the evidence on rates of incident psychiatric disorders before, during, and after pregnancy is limited. This study aimed to describe the calendar time trends and characterize and compare the risk of maternal psychiatric disorders before, during, and after pregnancy. Leveraging the national and regional registers in Sweden, we conducted a cohort study of all women who gave birth 2003-2019 in Sweden (1,799,010 pregnancies from 1,052,977 women). We identified any incident diagnosis of psychiatric disorders recorded during three periods: the preconceptional year, pregnancy, and the postpartum year. We calculated age and calendar year standardized incidence rate (SIR) of psychiatric disorders annually, and by week across three periods. We further estimated the incidence rate ratio (IRR) using the rate during corresponding preconceptional weeks as the reference. The SIR of maternal psychiatric disorder overall increased from 2003-2019, especially for preconceptional disorders. During the preconceptional year the weekly SIR of any psychiatric disorder was stable at around 25 per 1000 person-years. The SIR gradually decreased during pregnancy to a minimum of 4 per 1000 person-years and bounced back to the preconceptional levels during the postpartum year. This trend was similar in all subtypes of psychiatric disorders, except for depression and psychosis for which an increase was noted at 5-15 and 0-20 postpartum weeks, respectively. An increased incidence rate of maternal psychiatric disorder diagnosed before, during, and after pregnancy was found over time. Our findings suggest an increased risk of depression and psychosis shortly after delivery, although a lowered risk of other psychiatric disorders during and after pregnancy, compared to before pregnancy.