Increased maternal blood pressure can attempt to make up for lower cardiac output, ensuring that the fetuss growing brain receives enough oxygen and nutrients. The benefits of being able to walk upright and run on land have outweighed the disadvantages that come from bipedalism, including the placental diseases of pregnancy, such as gestational hypertension. Similarly, the advantages of having a large brain size have outweighed the deleterious effects of having a placenta that does not always convert the spiral arteries effectively, leaving humans vulnerable to contracting gestational hypertension. It is speculated that this was not the case with Neanderthals, and that they died out because their cranial capacity increased too much, and their placentae were not equipped to handle the fetal brain development, leading to widespread pre-eclampsia and maternal and fetal death.Gestational hypertension in the early stages of pregnancy (trimester 1) has been shown to improve the health of the child both in its first year of life, and its later life. However, when the disease develops later in the pregnancy (subsequent trimesters), or turns into pre-eclampsia, there begin to be detrimental health effects for the fetus, including low birth-weight. It has been proposed that fetal genes designed to increase the mothers blood pressure are so beneficial that they outweigh the potential negative effects that can come from pre-eclampsia. It has also been suggested that gestational hypertension and pre-eclampsia have remained active traits due to the cultural capacity of humans, and the tendency for midwives or helpers to aid in delivering babies.
Agoraphobia without a history of panic disorder (also called primary agoraphobia) is an anxiety disorder where the individual with the diagnosis does not meet the DSM-5 criteria for panic disorder. Agoraphobia typically develops as a result of having panic disorder. In a small minority of cases, however, agoraphobia can develop by itself without being triggered by the onset of panic attacks. Agoraphobia can be caused by traumatic experiences, such as bullying or abuse. Historically, there has been debate over whether agoraphobia without panic genuinely existed, or whether it was simply a manifestation of other disorders such as panic disorder, generalized anxiety disorder, avoidant personality disorder and social phobia. One researcher said: "out of 41 agoraphobics seen (at a clinic) during a period of 1 year, only 1 fit the diagnosis of agoraphobia without panic attacks, and even this particular classification was questionable...Do not expect to see too many agoraphobics without panic". In spite of this earlier skepticism, current thinking is that agoraphobia without panic disorder is indeed a valid, unique illness which has gone largely unnoticed, since those with the condition are far less likely to seek clinical treatment. Diagnostic criteria (DSM-IV-TR)
According to the DSM-IV-TR, a widely used manual for diagnosing mental disorders, the condition is diagnosed when agoraphobia is present without panic disorder where symptoms are not caused by or are unreasonable to an underlying medical problem or pharmacological influence. See also
Panic disorder
Agoraphobia

References
Spiti Raffaello, Scarpato Maria Alessandra, Spiti Alessandra (2011). "Primary agoraphobia specific symptoms: from natural information to mental representations".