By Margarita Nahapetyan
The latest research suggests that there could be a way to predict which pregnant moms-to-be are at risk for later postpartum depression. The research shows that women with an increased levels of corticotrophin-releasing hormone (CRH), which is produced by the placenta midway through pregnancy, are more likely to suffer with the condition.
CRH is normally produced in tiny amounts by the hypothalamus near the brain in response to stress. During pregnancy, the placenta produces hundred times more CRH than is normally produced by the hypothalamus. The hormone has been given a nickname, the "placental clock," because it is thought to prepare the woman's body for childbirth, said lead researcher Ilona S. Yim, an assistant professor of psychology at the University of California, Irvine.
After labor, levels of CRH and other hormones drop, causing hormone "withdrawal" form mother's body, and, therefore, creating big changes and a mess in the endocrine system. "Many factors may cause some women's bodies to produce more of this hormone during pregnancy. Evidence suggests that stress early in pregnancy could play a role," the researcher added.
For the study, the researchers took blood samples from one hundred pregnant women at two medical centers in California, at 15, 19, 25, 31 and 37 weeks' of pregnancy, and tested all of them for pCRH levels, as well as cortisol, a stress hormone, and adrenocorticotropic hormone (ACTH), which triggers the release of cortisol. They also examined the women for signs of depression during pregnancy and approximately 2 months, on average, after giving birth.
From all the women 16 developed postnatal depression. In each case, the women had had high levels of pCRH at 25 weeks into their pregnancies.
"Placental CRH in this study was a moderately sensitive and specific marker for PPD [postpartum depression] symptoms that allows for the correct identification of 75 per cent of women with future PPD symptoms, and at the same time was characterized by a low misclassification rate (24 per cent)," the researchers explained in the journal article.
Cortisol and ACTH levels did not seem to have any significant link to the development of postpartum depression. However, some evidence suggests the increase in pCRH during mid-pregnancy may be associated with an increase in cortisol early in pregnancy. "If we know early on that a woman is at high risk to develop postpartum depression, then we can implement interventions before symptoms actually occur," said Yim.
Recent studies found that about 19 per cent of all new mothers suffer from postpartum depression. The condition makes it difficult for the woman to handle everyday issues, and her newborn child and all the rest of the family suffer as well. Mothers in depression, according to scientists, usually pay much less attention to the feeding, nurturing, sleeping, and hygiene of their babies. If not addressed in time, women can become so depressed that some might even attempt suicide, and some harm or neglect their newborns. Also, at a later time children can develop problems with cognition, behavior, and social issues, when a parent is depressed.
Another negative side of postpartum depression is that the disorder is likely to return in the future. When mothers are at particular risk, intervention can begin before symptoms start appearing and, in many cases, it is possible to prevent the condition, before it starts showing any developing signs.
Yim suggests stress reduction measures, such as yoga, for mothers at risk. She says women who already have a history of depression are at greater risk of postpartum depression, as are women who have experienced stressful situations in their lives, who have a weak social support system, and who suffer from low self-esteem. When a woman feels depressed or stressed while being pregnant, her risk of developing postpartum depression is more likely to increase.
"This is the first study that implicates CRH in postpartum depression. That has implications for understanding this disorder," Yim said and added that the results needed to be examined on a larger scale.
The findings, published in the February issue of Archives of General Psychiatry, raise the possibility that a screening test for postpartum depression could one day become an important part of a woman's regular prenatal care. The scientists envision some type of routine blood screen which would coincide with the already scheduled routine blood work and may identify those at risk for postpartum depression. A preventative approach in combination with the possibility of therapy could be all that is needed.