Postpartum period
During the subacute postpartum period, psychological disorders may emerge. Among these are postpartum depression, posttraumatic stress disorder, and in rare cases, puerperal psychosis. Postpartum mental illness can affect both mothers and fathers, and is not uncommon. Early detection and adequate treatment is required. Approximately 25% – 85% of postpartum women will experience the "blues" for a few days. Between 7% and 17% may experience clinical depression, with a higher risk among those women with a history of clinical depression. Prevalence of PTSD following normal childbirth (excluding stillbirth or major complications) is estimated to be between 2.8 and 5.6% at 6 weeks postpartum.
Fetal origins hypothesis
Maternal stress has been linked to a number of negative outcomes for the developing fetus. Pregnant women who firsthand experienced the devastation of the World Trade Center attack on September 11, 2001 were studied to observe the effects of PTSD (post-traumatic stress disorder) on their child's future health. Of the women studied, those who developed PTSD following the attacks had lower basal cortisol levels than a control group. Their children, also, had lower basal cortisol levels than those not exposed to extreme prenatal stressors. The finding was strongest for the women who were in their third trimester during 9/11. Based on the findings that there was a trimester distinction in strength, conclusions can be drawn that the development of a vulnerability to stress was due at least in part to environment in utero. 9/11 is also correlated with lower birth weights of children born to women with Arabic sounding names following the attacks; this could possibly be due to fear of retaliation or stereotyping associations with the attackers. Stress has also been linked to preterm birth, as shown by research studies conducted following the Tarapaca, Chile earthquake in 2005, as well as the Northridge, California earthquake in 1994. Similar findings have been replicated for stressful life experiences and fetal outcomes in the Hurricane Katrina population of 2005. Women in New Orleans at the time who reported enduring multiple severe disaster experiences also had a significantly higher chance of delivering early or low birth weight children. Experiencing loss during pregnancy also influences postnatal outcomes. Women who experienced the death of a close family member, friend, or spouse, or were pregnant during a wartime conflict, were more likely to have children prematurely, and the children of these women were significantly more likely than the general population to suffer from schizophrenia in adulthood. Besides birth weight, mental health, and reduced cortisol levels, effects of stress during pregnancy have also been linked to impaired cognitive development in children as seen in the maternal population exposed to a severe snowstorm in Canada. Women who experienced the most stressful storm related events had children with detriments in cognitive, language, behavioral, and attention outcomes. Shockingly, the poorer performance by these children has persisted until the age of ten. Even job-related stress has been found to be associated with low birth weight and preterm birth. Working long hours, having temporarily employment, or reporting physically demanding job tasks showed "significant and strong" associations with poorer later birth outcomes. Findings for the job stress-birth association have been replicated by obstetricians at Cedars-Sinai Medical Center in Los Angeles. However, some research has found that moderate amounts of stress and cortisol passed on to a developing fetus are actually beneficial, perhaps acting to give organs a "workout" prior to birth. Further cementing the theory that maternal emotional state can impact child development are the sound research findings that women who are clinically or slightly depressed during pregnancy are more likely to have children with low birth weight, putting them at risk for future health concerns of their own. On May 12, 2008, a raid took place in Postville, Iowa, where 389 workers at a meat processing factory were arrested and held for questioning. Out of the 389 workers detained, 270 served sentences and most were deported to primarily Mexico and Guatemala. Among those arrested 98% were Latino as they were suspected of being illegal immigrants. Latino families feared future deportations and future raids creating psychological stress on Latinos in the area. In relation to maternal stress a study was conducted which found that Latino babies born 37 weeks after the event experienced a 24% greater risk of lower birth (about 5.5 pounds) weight than babies born in other years. The risk for preterm births was also higher for Latina women when compared to non-Latina White women.