For example, in the prolonged pregnant women with oligohydramnios, resistance index in the fetal renal artery is higher than it is in the controls, which are without oligohydramnios [20]; additionally, cyclooxygenase-2 inhibitor nimesulide and long-term diclofenac exposure are associated with oligohydramnios [21, 22]. This evidence concerns the gene PTGS2 and oligohydramnios.