Is parity status associated with bipolar disorder clinical features, severity of evolution?

Objective
To assess prospectively the association of the number of past pregnancies on the evolution of bipolar disorder (BD).
Methods
Data were drawn from the 2 waves of the National Epidemiologic Study of Alcohol and Related Conditions (NESARC), a representative sample of the US population of 34,653 participants. All women diagnosed with BD were included. The number of children and BD’s characteristics, i.e. BD type, age of onset, hospitalization and suicide attempt, and lifetime psychiatrics comorbidity were assessed at wave 1. Mood episode and BD’s characteristics were also assessed at wave 2.
Results
In the sample of 1190 women with BD, 27% had no child, 17% had one, 25% had two 31% had three children or more. Women with at least two children were more likely to have BD I, to report hypomania and suicide attempt during the follow-up than women without child. Parity was not associated with other characteristics of BD, nor with the severity and course of the illness.
Limitations
Not provide information on pregnancies not ending to a delivery.
Conclusion
Parity is associated with a higher incidence of hypomania and suicide attempt during a 3-years follow-up in women with BD.