When the fetuss trophoblast does not fully extend into the uterine wall, the spiral arteries do not become fully converted into low-resistance channels. It has been found that this incomplete conversion of spiral arteries increases the resistance to uterine blood flow during pregnancy, and that this occurrence was associated with gestational hypertension. One potential cause of this incomplete breach of the spiral arteries that leads to gestational hypertension is a mistaken immune response by the maternal tissue, reaction to the alien fetal tissue. Therefore, it is clear that the complication of gestational hypertension has roots in the early implantation of the fetus in the uterine wall, an implantation technique that is unique to humans.The highly invasive placenta that is found in humans is thought to be linked to humans high circulating levels of the hormones CG and hCG. It has been shown that the higher the levels of these hormones, the deeper the trophoblasts invasion into the uterine wall. Instances of gestational hypertension and pre-eclampsia have been shown to occur when the invasion of the uterine wall is not deep enough, because of lower CG and hCG levels in the mother. Evolutionary tradeoff
Despite these risks for gestational hypertension, the hemochorial placenta has been favored because of its advantages in the way that it aids in diffusion from mother to fetus later in pregnancy. The bipedal posture that has allowed humans to walk upright has also led to a reduced cardiac output, and it has been suggested that this is what necessitated humans aggressive early placental structures.
Pyromania is generally harder to treat in adults, often due to lack of cooperation by the patient. Treatment usually consists of more medication to prevent stress or emotional outbursts, in addition to long-term psychotherapy. In adults, however, the recovery rate is generally poor, and if an adult does recover, it usually takes a longer period of time. History
Pyromania was thought in the 1800s to be a concept involved with moral insanity and moral treatment, but had not been categorized under impulse control disorders. Pyromania is one of the four recognized types of arson, alongside burning for profit, to cover up an act of crime and for revenge. Pyromania is the second most common type of arson. Common synonyms for pyromaniacs in colloquial English include firebug (US) and fire raiser (UK), but these also refer to arsonists. Pyromania is a rare disorder with an incidence of less than one percent in most studies; also, pyromaniacs hold a very small proportion of psychiatric hospital admissions. Pyromania can occur in children as young as age three, though such cases are rare. Only a small percentage of children and teenagers arrested for arson are child pyromaniacs. A preponderance of the individuals are male; one source states that ninety percent of those diagnosed with pyromania are male. Based on a survey of 9,282 Americans using the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, impulse-control problems such as gambling, pyromania and compulsive shopping collectively affect 9% of the population.