Psychoneuroimmunology in Pregnancy

Psychoneuroimmunology in Pregnancy
A large motivating factor for my enrollment in this class was to further my understanding of the psychoneuroimmunology (PNI) framework. Hopefully this framework will guide my dissertation research as well as my future research trajectory. As the title implies, my focus resides within the realm of women’s health and pregnancy outcomes in particular. So, stumbling upon this article was of great interest to me.
Christian (2011) presents a review of the use of the PNI framework to elucidate biological mechanisms by which stress may affect pregnancy outcomes, in particular preterm birth. Preterm birth currently affects 12-13% of all births in the United States (Christian, 2011). This rate is significantly higher than that of other developed countries. Preterm birth is a leading cause of infant mortality. Those who survive are at a high risk of serious health complications including respiratory, gastrointestinal, nervous system and immune system problems. Long term consequences can include cerebral palsy, mental retardation, learning disabilities, hearing and vision problems, and poor growth.
Despite advancing technologies, improved identification of risk factors, and public health initiatives, preterm birth has remained a substantial problem in the U. S. Recent theories are centering on the impact of racial disparities and the associated chronic stress which is associated with discrimination aimed at minority groups. The disparities in preterm birth among African American women and women of other races cannot be explained by demographic factors.
Christian (2011) relates that stress measured in a variety of ways is consistently shown to be an independent risk for preterm birth. Women who report greater stress are 1.5 to 3 times more likely to give birth preterm. Despite the availability of this information, few studies have investigated the potential biological mechanisms. Christian (2011) directs our attention to the immune system relating the well known link between increased stress levels and dysregulation of the immune response. Alterations include increased levels of circulating inflammatory cytokines, greater inflammatory responses to psychological stressors, and increased inflammatory responses to in-vitro and in-vivo biological challenges.
A healthy pregnancy is characterized by an attenuated proinflammatory cytokine production in response to both in-vitro and in-vivo biological responses. This adaptation may prevent fetal rejection by the maternal system as well as protect the fetus from infection which may occur in the mother. Christian and colleagues investigated the relationship between psychosocial factors and serum proinflammatory cytokines in 60 women sampled from the Ohio State University prenatal clinic. The population is diverse and predominantly disadvantaged. Women were assessed at one time point in the pregnancy, the second trimester. Those with higher depressive symptoms had higher levels of circulating IL-6 and TNF. These increased levels of pro-inflammatory cytokines can trigger preterm contractions, cervical ripening, and rupture of the membranes, all of which can lead to subsequent preterm birth.
Of particular interest in this article was the discussion regarding the use of the influenza vaccine to study an in-vivo immune challenge among pregnant women. Secondary to obvious ethical concerns, human in-vivo studies of the immune system are not conducted in the pregnant population. However, the flu vaccine presents a unique opportunity for such a study. Pregnant women are considered at high-risk for significant complications arising from influenza. Consequently both the CDC and the American College of Obstetricians and Gynecologists recommend that all pregnant women be immunized against influenza. Christian and colleagues studied the inflammatory response of 22 pregnant women immunized with the flu vaccine. Women were also evaluated for depressive symptoms utilizing the Center for Epidemiological Studies Depressive Scale.
Extant research has demonstrated greater inflammatory response to vaccines in older individuals with depressive symptoms as well as men with carotid artery disease. This data suggests different responses to vaccines among those who are experiencing an inflammatory condition. Christian and colleagues demonstrated that psychosocial factors are associated differential inflammatory responses to the influenza vaccine in pregnant women. Christian’s study provides support to the theory that increased psychological stress predicts sensitization of the immune system to in-vivo immune triggers during pregnancy.
Further research on this subject is needed to elucidate the impact of stress upon the immune system during pregnancy. Research may focus on circulating cytokine levels, inflammatory response to immune triggers, and immune response to psychosocial stressors. Investigation of these factors may help to illuminate biological mechanisms involved in preterm labor and thereby decrease the rate of adverse pregnancy outcomes and infant mortality.
Christian, L. M. (2011).

Psychoneuroimmunology in pregnancy: immune pathways linking stress
With maternal health, adverse birth outcomes, and fetal development. Neuroscience and
Biobehavioral Reviews. Doi;10.1016/j.neurobiorev.2011.07.005.