Fertility and fecundity are usually considered signs of social and emotional well-being. Bipolar disorder (BD) is a prevalent psychiatric disease that influences the individual's life style and behaviours. Some studies have addressed the issue of fecundity among women with bipolar disorder but few have focused on determining the differences between disease subtypes, which is expected, taking into account the studied differences in demographic measures.

To examine the fecundity of a population of women with bipolar disorder.

The aim of this study is to compare the fecundity among women diagnosed with subtypes I to IV of BD, according to Akiskal's bipolar spectrum disorder classification.

A total of 108 female outpatients were divided into four groups. We analyzed number of offspring and demographic features between patients with different subtypes of BD using multivariate analyses.

Our results showed a significantly higher average number of children for BD IV patients when compared with BD I patients. Although not reaching statistical significance, BD I patients had less offspring than BD II and BD III patients. BD I patients had lower marriage rates compared to the other groups.

Our results suggest that the subtype of bipolar disorder influences fecundity and behaviours, as is expressed by the lower number of marriages seen in BD I patients. We found that fecundity is significantly impaired among BD I patients, which may imply that female with more severe disorders are less likely to become parents. Fecundity is higher among BD IV patients, which makes a way to speculate about the adaptive role of hyperthimic temperamental traits.