of clear vaginal discharge in pregnancy. Other tests for detecting amniotic fluid mainly include nitrazine paper test and fern test. One main test that is performed on amniotic fluid is the L/S ratio test (lecithin/sphingomyelin). This test is used to determine fetal lung maturity. Both lecithin and sphingomyelin are lung surfactants that are present in increasing amounts in the maturing fetus, though past week 33, sphingomyelin levels remain relatively constant. Measuring a ratio of L/S of 2:1 or greater indicates that the fetus can be safely delivered, with functioning lungs. Complications related to amniotic fluid Too little amniotic fluid is called oligohydramnios. In a minority of cases it can be a cause of problems for the mother and baby. These include contracture of the limbs, clubbing of the feet and hands, and also a life-threatening condition called hypoplastic lungs. The Potter sequence refers to a constellation of findings related to insufficient amniotic fluid. On every prenatal visit, the obstetrician, gynaecologist or midwife should measure the patient's fundal height with a tape measure. It is important that the fundal height be measured and properly recorded to track proper fetal growth and the increasing development of amniotic fluid. The obstetrician, gynaecologist or midwife should also routinely ultrasound the patient—this procedure will also give an indication of proper fetal growth and amniotic fluid development. Oligohydramnios can be caused by infection, kidney dysfunction or malformation (since much of the late amniotic fluid volume is urine), procedures such as chorionic villus sampling (CVS), and preterm premature rupture of membranes (PPROM). Oligohydramnios can sometimes be treated with bed rest, oral and intravenous hydration, antibiotics, steroids, and amnioinfusion. The opposite of oligohydramnios is polyhydramnios, an excess volume of amniotic fluid in the amniotic sac. Amniotic fluid embolism is a rare but very often fatal condition for both mother and child. Medical applications It is being used in some surgeries of the outside of the eye. It is also being studied for some orthopaedic conditions. Stem cell research Recent studies show that amniotic fluid contains a considerable quantity of stem cells. These amniotic stem cells are pluripotent and able to differentiate into various tissues, which may be useful for future human application. Some researchers have found that amniotic fluid is also a plentiful source of non-embryonic stem cells. These cells have demonstrated the ability to differentiate into a number of different cell-types, including brain, liver and bone. It