February 5, 2009

Hormone linked to postnatal depression

[Posted: Wed 04/02/2009 by Deborah Condon]

Women who have higher levels of a specific hormone midway through their pregnancy may be more likely to develop postnatal depression, the results of a new study indicate.

According to US researchers postnatal depression usually begins within four to six weeks of giving birth and risk factors include a history of depression, stressful life events and a lack of social support. However these risk factors cannot be attributed to everyone who goes on to develop this type of depression.

The team at the University of California in Irvine found a possible link between a hormone produced by the placenta, known as placental corticotropin-releasing hormone (pCRH), and postnatal depression.

They studied the hormone in 100 pregnant women. Blood samples were taken when the women were 15,19, 25, 31 and 37 weeks pregnant. Symptoms of depression were also assessed at the last four pregnancy visits and again around eight weeks after delivery.

Sixteen of the participants had developed postnatal depression symptoms by the time of the follow-up visit. According to the researchers, the levels of pCRH when the women were 25 weeks pregnant strongly predicted this development.

In fact, three-quarters of women with future postnatal depression could be identified using the pCRH marker and only 24% would be misclassified, the team said.

The narrow window of time in which pCRH levels predicted depression symptoms – between 23 and 26 weeks gestation – roughly coincided with a surge in levels of the hormone.

"We do not know which factors may precipitate the surge in pCRH, but some evidence suggests an association between elevated cortisol (stress hormone) early in pregnancy and increased pCRH late in pregnancy," the team said.

They added that their findings had important clinical and theoretical implications.

"If our results are replicable, it may be considered useful to implement a pCRH postnatal depression screen into standard prenatal care. Because blood tests to screen for gestational diabetes are typically performed at 24 to 28 weeks' gestational age, a potential postnatal depression screen could be completed at the same time,” they explained.

Details of these findings are published in the journal, Archives of General Psychiatry.

For more information on pregnancy, see…http://www.mum.ie

For more information on depression, see…http://www.irishhealth.com/clin/depression/index.html