Being happy, relaxed or in control was associated with a 60% reduction in odds of miscarriage compared with all other women (adjusted [including nausea] odds ratio: 0.41). Conversely, women who reported feeling ‘stressed’, ‘anxious’, ‘depressed’, ‘out of control’ or ‘overwhelmed’ in the first 12 weeks of pregnancy had much higher odds of miscarriage than those who described themselves as happy, relaxed or in control. This effect increased to a tripling in odds after adjusting for confounding by nausea. Women who reported feeling ‘other’ emotions (which tended to be negative, including guilt and fear) also had increased odds of miscarriage (odds ratio: 1.70).
http://onlinelibrary.wiley.com/doi/10.1111/j.1471-0528.2006.01193.x/full
Higher post traumatic stress disorder symptom counts correlated with worse overall perinatal outcomes summarized by an Optimality Index Score.
http://linkinghub.elsevier.com/retrieve/pii/S1526952305001972
Stress was measured by the Perceived Stress Scale (PSS), the Prenatal Social Environment Inventory (PSEI) and the Index of Spousal Abuse (ISA) prior to confirmation of miscarriage . Blood samples were collected to measure cortisol and sex hormone levels. High psychosocial stress during early pregnancy was not related to miscarriage but high stress was associated with substance use during pregnancy.
http://linkinghub.elsevier.com/retrieve/pii/S1047279702004192
Overall, there was no evidence that working full time had a worse effect on odds of miscarriage than working part time or staying at home. However, those reporting that their job was generally stressful and/or demanding had significantly higher odds of miscarriage than those who did not (odds ratio 1.30).
http://onlinelibrary.wiley.com/doi/10.1111/j.1471-0528.2006.01193.x/full
In studies conducted by Alice Domar, PhD, at Harvard's Mind-Body Institute, women who underwent stress reduction therapy saw dramatic increases in their ability to get pregnant. In fact, even women who were already undergoing fertility treatments had more successful outcomes when stress was kept under control.
http://www.webmd.com/baby/features/getting-pregnant-easy-ways-to-encourage-fertility?page=2
In the Guatemalan study, 22 pregnancies occurred in 16 women, and each woman's cortisol levels were measured against their own baseline levels. Researchers found that 90 percent of women, whose ages ranged from 18 to 34, with elevated levels of the stress-induced hormone miscarried during the first three weeks of pregnancy, compared to 33 percent of those with normal levels.
http://www.sciencedaily.com/releases/2006/02/060221091715.htm
Epidemiological studies suggest the role of stress in miscarriage and exposure to stress induces miscarriage in mice via a significant reduction in progesterone levels, accompanied by reduced serum levels of progesterone induced blocking factor. These effects are corrected by progesterone supplementation. These findings indicate the significance of a progesterone-dependent immuno-modulation in maternal tolerance of the fetus.
http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0897.2007.00512.x/full
Stress is known to be abortogenic in animals and humans. An increased decidual release of cytokines such as TNF-alpha and reduction in TGF-beta 2-related immunosuppressive activity has been proposed as the triggering mechanism. Uterine mast cells show activation as reflected by degranulation after stress exposure of pregnant mice and mast cells might be the cellular link between the neurotransmitter substance P and increase in decidual TNF-alpha release that leads to miscarriage.
http://www.ncbi.nlm.nih.gov/pubmed/9138459
Stress induces in loading situations a changing action of elevated stress hormones adrenaline, noradrenalin++ and cortisol on the metabolism of other hormones, e.g. a decrease of serum progesterone and an increase of estrogen and thyroxine-level. Therefore the physiological balance of the organism is disturbed. Because informations of the nervous system are transmitted to the utero-placental unit in this way there are disturbances e.g. reduction of fetal oxygenation, advancement of uterine contractility and possible stimulation of labor. Troubles of the immunologic protection of pregnancy by stress have been considered.
http://www.ncbi.nlm.nih.gov/pubmed/3291490