Explain the physiology and functions of amniotic fluid during pregnancy. Refer to the abnormalities of amniotic fluid specifically polyhydramnios and the implications of this condition on mortality.

Amniotic fluid is an alkaline fluid that is clear, pale or straw-coloured. The composition of amniotic fluid changes throughout pregnancy and depends on gestation, however is 98% water. Contents also include electrolytes, proteins, protein derivatives such as urea and creatine, carbohydrates, lipids, hormones, enzymes, desquamated fetal cells, vernix and lanugo.

Amniotic fluid is first evident as droplets at three weeks post fertilisation. At 4-8 weeks the volume has increased to approximately 20 millilitres, which pushes out the amnion until it reaches and lines the chorion….(short extract)