These proposals may explain why premature infants spend 2.5% of their time hiccuping, possibly gulping like amphibians, as their lungs are not yet fully formed.The phylogenetic hypothesis may explain hiccups as an evolutionary remnant, held over from our amphibious ancestors. This hypothesis has been questioned because of the complexity of the mammalian hiccup reflex compared to the amphibian breathing reflex, the fact that it does not explain the reason for glottic closure, and because the very short contraction of the hiccup is unlikely to have a significant strengthening effect on the slow-twitch muscles of respiration.Fetal intrauterine hiccups are of two types. The physiological type occurs prior to twenty-eight weeks after conception and tends to last five to ten minutes. These hiccups are part of fetal development and are associated with the myelination of the phrenic nerve, which primarily controls the thoracic diaphragm.The phylogenetic and the burping hypotheses are not mutually exclusive. The phylogeny hypothesis could explain how the hiccup reflex might have evolved, while the "Burping Hypothesis" could explain why it would offer enough of an evolutionary advantage to persist and increase in complexity. Duration
Episodes of hiccups usually last just a few minutes, doing nothing worse than annoying those affected and amusing bystanders, but prolonged attacks can be serious, with a cause difficult to diagnose. Such attacks can cause significant morbidity and even death. An episode lasting more than a few minutes is termed a bout; a bout of over 48 hours is termed persistent or protracted. Hiccups lasting longer than a month are termed intractable.
Pitting edema (unusual swelling, particularly of the hands, feet, or face, notable by leaving an indentation when pressed on) can be significant, and should be reported to a health care provider. In general, none of the signs of pre-eclampsia are specific, and even convulsions in pregnancy are more likely to have causes other than eclampsia in modern practice. Further, a symptom such as epigastric pain may be misinterpreted as heartburn. Common features of pre-eclampsia which are screened for during pre-natal visits include elevated blood pressure and excess protein in the urine. Diagnosis depends on finding a coincidence of several pre-eclamptic features, the final proof being their regression within the days and weeks after delivery. Causes
There is no definitive known cause of pre-eclampsia, though it is likely related to a number of factors. Some of these factors include:
Abnormal placentation (formation and development of the placenta)
Immunologic factors
Prior or existing maternal pathology—pre-eclampsia is seen more at a higher incidence in individuals with pre-existing hypertension, obesity, or antiphospholipid antibody syndrome or those with a history of pre-eclampsia
Dietary factors, e.g. calcium supplementation in areas where dietary calcium intake is low has been shown to reduce the risk of pre-eclampsia
Environmental factors, e.g.