Amniotic Fluid Index Chart

Amniotic fluid is a liquid of a clear or a little yellow color that is found in the uterus of pregnant women, which can becalled liquor amnii. The amniotic liquid surrounding the fetus is quite essential to the baby's development.

To estimate the volume of amniotic fluid within the uterus, the amniotic fluid index is used, which is measured against the amniotic fluid index chart.

Amniotic Fluid Index Chart

When a woman is pregnant, she often undergoes a series of ultrasound examinations to attain a fetal biophysical profile. The amniotic fluid index (or AFI) is used to estimate the well-being of the fetus by doing an ultrasound of the uterus to estimate the levels of amniotic fluid levels in the uterus.

There areseveral approachesto test; the most commonly used methods are the four-quadrant techniqueand the 'single deepest pocket'. The amniotic fluid index chart shows the average volume of amniotic fluid in a pregnant woman based on gestational agein millimeter.

Amniotic Fluid Index Chart Percentile Values

Week

2.5th

5th

50th

95th

97.5th

16

73

79

121

185

201

17

77

83

127

194

211

18

80

87

133

202

220

19

83

90

137

207

225

20

86

93

141

212

230

21

88

95

143

214

233

22

89

97

145

216

235

23

90

98

146

218

237

24

90

98

147

219

238

25

89

97

147

221

240

26

89

97

147

223

242

27

85

95

146

226

245

28

86

94

146

228

249

29

84

92

145

231

254

30

82

90

145

234

258

31

79

88

144

238

263

32

77

86

144

242

269

33

74

83

143

245

274

34

72

81

142

248

278

35

70

79

140

249

279

36

68

77

138

249

279

37

66

75

135

244

275

38

65

73

132

239

269

39

64

72

127

226

255

40

63

71

123

214

240

41

63

70

116

194

216

42

63

69

110

175

192

Techniques and Values of Amniotic Fluid Index Charts

Technique

Using the umbilicus and the linea nigra as horizontal and vertical axis, an imaginary divide is created inside the uterus, which is split into four quadrants. The deepest pocket without fetal parts or umbilical cord is then measured in millimeters or centimeters vertically. The sum of the four quadrants, in millimeters or centimeters, is amniotic fluid index. Usually, the normal value of amniotic fluid index varies from 50 mm to 250 mm (or 5 cm to 25 cm).

Values

Normal AFI varies from 80 mm to 180mm. An average AFI level is 80 mm to 140 mm when you are in your 20 weeks to 35 weeks of pregnancy. After 35 week, AFI levels usually begin to reduce.

The AFI < 50-60 mm is assumed as oligohydramnios, while AFI >250mm is assumed as polyhydramnios. With the pregnancy process going on, the AFI values are changing, and the percentile for fetus age is usually referred as the cutoff value.

What If I Have Abnormal Amniotic Fluid Levels?

If there are high amounts of amniotic levels in a mother's uterus then it is known as polyhydramnios, whereas having small amounts of amniotic fluid can lead to oligohydramnios. With the amniotic fluid index chart above, you will wander what are the possible complications along with oligohydramnios and polyhydramnios?

Low Amniotic Fluid Levels

Having low levels of amniotic fluid inside the uterus during pregnancy can lead to numerous problems, which include miscarriage, premature birth, and stillbirth. There are often no symptoms experienced by the mother, except for their belly not growing in alignment with their duration of pregnancy, being smaller than it should.

High Amniotic Fluid Levels

The symptoms of polyhydramnios for this include edema, difficulty breathing, and excessive weight gain. Polyhydramnios can lead to many of the same complications as oligohydramnios, and the extra fluid can leak through the vagina in rare instances. Polyhydramnios can also lead to certain congenital complications, including Down’s syndrome.

Possible Treatments for Polyhydramnios and Oligohydramnios

Unfortunately, effective treatments for polyhydramnios and oligohydramnios are limited. In some cases of oligohydramnios, extra fluid has been added to the mother's amniotic sac in an effort to increase amniotic fluid levels within the uterus. The opposite is done in treatment of polyhydramnios, where a syringe is inserted into the amniotic sac to drain excess fluid. If needed, this option can be done more than once.

If the cause of the condition is known, then other treatmentsmay be applied. If a fetal bladder obstruction is the cause of oligohydramnios, a small tube can be placed in the bladder to allow the fluid to flow into the amniotic sac.

Pharmaceutical drugs are sometimes prescribed to treat polyhydramnios, such as indomethacin, but concerns have been raised over implications to the unborn baby and other side-effects.

 
 
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