Aim. Maternal stress hormones may play a role in timing of delivery through their interaction with placental hormone production. The placenta produces prodigious amounts of Corticotropin-releasing hormone (CRH), which is up-regulated by both foetal and maternal cortisol. By mid gestation, CRH levels are correlated inversely with gestational length Although it is not established whether CRH causes delivery, the ability of CRH to stimulate cytokine release from decidua and amnion in vitro and its potentiating effect on oxytocin-stimulated myometrial contraction strongly suggest a direct causal role in triggering parturition. In vitro studies have shown that cultured placental cells increase CRH production in response to cortisol and catecholamines. Different studies reported associations between maternal race/ethnicity, social position, low family income and CRH levels. Placental CRH promotes foetal cortisol and sulfoconjugated dehydroepiandrosterone (DHEAS) production and these steroids return via the umbilical circulation to the placenta where cortisol promotes further CRH secretion and DHEA-S is converted to oestrogen. It has been suggested that in primates, increased oestrogen synthesis prior to labour is mediated by increased availability of fetally-derived androgen substrates, mainly DHEAS. But DHEAS act also as a neurosteroid and his involvement on depression syndromes, anxiety disorders, stress responses to different stress stimuli, memory processes need to be considered. Increased level of DHEAS has been reported in PTSD subjects and in IUGR complicated pregnancies.
Study design. 500 consecutive healthy subjects at 40 weeks of pregnancy will enter the study We will assess 1) General demographic background. 2) Description of the present and past pregnancies. 3) Personal medical history and obstetrical data 4) foetal ultrasound and Doppler data 5) Psychological stress evaluation for: Anxiety (STAI TRAIT anxiety inventory Spielberger CD 1993); Depression ( Beck depression inventory II Beck 2006); Dissociation ( Dissociative experience scale DES, Carlson 1993); Self Defining autobiographical memories (Jefferson A Singer, Pavel S Blagov); Parental bonding instrument (PBI Parker G Tupling H Brown LB); Impact of Event Scale -revised ( Weiss DS and Marmar CR 1997),
6) hormonal assays for cortisol/ DHEAS ratio and Placental CRH. We expect that 5-10 % of subjects will deliver preterm and that 10 % will have a prolonged pregnancy. Differences intra groups and between groups will be evaluated.
Objective. There are numerous intersecting pathways¿neural, endocrine, immune, vascular¿through which an accumulating burden of psychosocial stressors might affect pregnancy outcome. We will try to link specific chronic stressors (such as social or economic position) to perceived stress (such as perceived life events impact or anxiety) to physiologic stress responses (such as blood pressure, or CRH and Cortisol /DHEAS ratio) and delivery timing.