Hormones in placenta linked to post-natal depression
Levels of a hormone produced by the placenta half way through pregnancy could provide a test for women at risk of post-natal depression, new research suggests.
A “surge” of the hormone when women were between 23 and 26 weeks pregnant was strongly associated with later post-natal or “postpartum” depression, a US study found.
The condition, which usually shows itself between four and six weeks of giving birth, is distinct from the brief period of tearfulness known as “baby blues”.
Around one in 500 new mothers are severely affected and in some cases have been driven to suicide or infanticide.
Research suggests that more than 17,000 women in the UK may suffer undetected post-natal depression each year.
Although many factors are believed to contribute to the problem, including a history of depression, anxiety and stress during pregnancy, low self esteem and lack of social support, these alone cannot explain why some women are affected and others are not.
Scientists in California studied 100 pregnant women to test whether levels of placental corticotropin-releasing hormone (pCRH) may play a role.
Of the total, 16 women went on to develop post-natal depression symptoms.
When their levels of pCRH were examined it was found that within a narrow band of pregnancy the hormone gave a good indication of risk.
The findings, reported in the journal Archives of General Psychiatry, showed that the hormone could be used to identify about three quarters of pregnant women expected to suffer from post-natal depression. Only about 24% of women tested for the hormone were likely to be misclassified.
What caused the surge of pCRH between weeks 23 and 26 of pregnancy was not known, said the scientists led by Dr Ilona S Yim, from the University of California at Irvine.
Some evidence suggested an association between elevated levels of the stress hormone cortisol early in pregnancy and increased pCRH levels late in pregnancy.
The authors wrote: “Our study has important clinical and theoretical implications.
“If our results are replicable, it may be considered useful to implement a pCRH PPD (postpartum depression) screen into standard prenatal care. Because blood draws to screen for gestational diabetes are typically performed at 24 to 28 weeks’ gestational age, a potential PPD screen could be completed at the same time. In addition, a better understanding of the role of pCRH in the pathophysiologic mechanism leading to PPD may contribute to the development of preventions targeted at this rather common disorder.”
