Signs and symptoms
Because postterm pregnancy is a condition solely based on gestational age, there are no confirming physical signs or symptoms. While it is difficult to determine gestational age physically, infants that are born postterm may be associated with a physical condition called postmaturity. The most common symptoms for this condition are dry skin, overgrown nails, creases on the babys palms and soles of their feet, minimal fat, abundant hair on their head, and either a brown, green, or yellow discoloration of their skin. Doctors diagnose postmature birth based on the babys physical appearance and the length of the mothers pregnancy. However, some postmature babies may show no or few signs of postmaturity. Baby
Reduced placental perfusion – Once a pregnancy has surpassed the 40-week gestation period, doctors closely monitor the mother for signs of placental deterioration. Toward the end of pregnancy, calcium is deposited on the walls of blood vessels, and proteins are deposited on the surface of the placenta, which changes the placenta. This limits the blood flow through the placenta and ultimately leads to placental insufficiency, and the baby is no longer properly nourished. Induced labor is strongly encouraged if this happens. Oligohydramnios – Low volume of amniotic fluid surrounding the fetus. It is associated with complications such as cord compression, abnormal heart rate, fetal acidosis, and meconium amniotic fluid. Meconium aspiration syndrome – Respiratory compromise secondary to meconium present in infants lungs. Macrosomia – Estimated fetal weight of ≥ 4.5 kg. It can further increase the risk of prolonged labor and shoulder dystocia.
The fourth electron from another cytochrome c flows through CuA and cytochrome a to the cytochrome a3–CuB binuclear center, reducing the Fe4+=O to Fe3+, with the oxygen atom picking up a proton simultaneously, regenerating this oxygen as a hydroxide ion coordinated in the middle of the cytochrome a3–CuB center as it was at the start of this cycle. Overall, four reduced cytochrome cs are oxidized while O2 and four protons are reduced to two water molecules. : 841–5

Inhibition
COX exists in three conformational states: fully oxidized (pulsed), partially reduced, and fully reduced. Each inhibitor has a high affinity to a different state. In the pulsed state, both the heme a3 and the CuB nuclear centers are oxidized; this is the conformation of the enzyme that has the highest activity. A two-electron reduction initiates a conformational change that allows oxygen to bind at the active site to the partially-reduced enzyme. Four electrons bind to COX to fully reduce the enzyme. Its fully reduced state, which consists of a reduced Fe2+ at the cytochrome a3 heme group and a reduced CuB+ binuclear center, is considered the inactive or resting state of the enzyme.Cyanide, azide, and carbon monoxide all bind to cytochrome c oxidase, inhibiting the protein from functioning and leading to the chemical asphyxiation of cells. Higher concentrations of molecular oxygen are needed to compensate for increasing inhibitor concentrations, leading to an overall reduction in metabolic activity in the cell in the presence of an inhibitor.