Fluid inside the womb called Liquor amni gives an indirect idea about pregancy wellibeing

How do we determine the  amniotic Fluid  volume or AFI ??  

It was originally described by Phelan   and associates. In order to calculate the  AFI   the abdomen is divided  into four quadrants   in which the  umbilicus divides the upper  and    lower  halves  and the linea  nigra   divides   the right  and left halves. With  th patient   supine the linear  transducer  is placed along the maternal anterior   abdominal  wall and   held pre  perpendicular  to the floor. The MVP=maximum  vertical  pocket  of fluid   ( usually  reported  in centimeters )   equals the sum of  largest single vertical pocket of fluid  that is  at least  1 cm  in width  obtained following  the same  criteria described here .

Drawbacks of MVP?? Mean vertical pocket  has been   shown to result in over diagnosis of low AFV  ( oligohydramnios ).

So also Colour Doppler in estimation of AFI-may be inappropriate:--In a  study   by Magann and colleagues     the use of color   Doppler   inappropriately  diagnosed  21% of  women with   low AFV  who actually had normal   dye determined AFVs . In  addition  color Doppler  did not identify  any more  pregnancies  with true dye determined low AFVs compared  with traditional   gray  scale ultrasound imaging .

Which definition U will follow : Choice is yours: What do we mean by Low AFV   (referred to as oligohydramnios) ? Oligohydramnios   has been variously defined as any one of the following. A) a total volume less than 200 mL( Horsager,R :Obstet Gynecol  83:955-958,1994.)  or  B) total volume  less  than 500 mL ( Magann EF et al: Am J Obstet Gynecol 167: 1533-1537,1992m, C)   AFI -a value  below the 5 th percentile  for gestational   age  or some have also defined as D) an SDP less than 2 cm an AFI : E)   AFI  less than  5 cm,  or even  F) a subjectively low AFV.

Many criteria are there  -Which criteria U are going to follow or your sonologist will adopt or adhered to it is up to him/ her:  But final Choice is yours as pt trust on you. : Then what is hydramnios?? An increased  AFV ( referred to as polyhydramnios ) is defined    as any  one of the four of following : A) a total volume  greater  than 2000 mL :: B) a value above  the 95^th  or 97  percentiles for gestational age :: C) an SDP  greater  than   or equal  to 8 cm ::  D) An  AFI  greater  than or equal to 24 cm :: or E)  greater  than 25 cm or like oligohydramnios  a subjectively increased  AFV,