New York, Jan 19 (IANS): A study has found that women who experienced mood disorders during pregnancy may be at risk for more severe postpartum depression (PPD) than those whose symptoms begin after birth.

Also called postnatal depression, PPD is a type of clinical depression which can affect women after childbirth.

"Clinicians should be aware of the diverse presentation of women with postpartum depression," said Samantha Meltzer-Brody, director of the perinatal psychiatry programme at the University of North Carolina's centre for women's mood disorders.

In the study, data from more than 10,000 women collected in previous studies were analysed using a statistical technique called latent class analysis widely used in psychiatry.

The clinical characteristics found to be most relevant in defining the three subtypes were the timing of symptom onset (beginning during pregnancy or after birth), the severity of symptoms (including thoughts of suicide), a history of a previous mood disorder and whether or not a woman had medical complications during pregnancy or childbirth.

Women with postpartum depression may experience any of three distinct subtypes of clinical presentation, the researchers found.

"A thorough assessment of a women's history is necessary to guide appropriate clinical and treatment decisions," Meltzer-Brody said.

We now understand that postpartum depression can have onset of symptoms that may begin in pregnancy, she added.

The study was published in the journal The Lancet Psychiatry.