CURRENT TECHNIQUE USED FOR AMNIOTIC FLUID DETECTION

Nitrazine (pH)



NITRAZINE TEST



Technique:

Amniotic fluid is alkaline and turns Nitrazine pH indicator blue

Accuracy:

False positive results are up to 17.4%

False negative results are 12.9%

Sensitivity 90.7%

Specificity 77.2%

Drawbacks:

Speculum exam is required to collect the sample. False-positive results may be caused by cervicitis, vaginitis (bacterial vaginosis or Trichomonas), alkaline urine, blood, semen, or antiseptics.

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Ferning

:Technique

Arborization pattern (crystallization) of dry amniotic fluid as seen through a microscope

Accuracy:

False positive results are 5-30%

False negative results are 12.9%

Sensitivity 51.4% (no labor)

Specificity 70.8% (no labor)

Drawbacks:

Speculum exam is required to collect the sample. Requires microscope. False positives may result from contamination of slide with fingerprints or contamination with semen and cervical mucus. False negative may be caused by dry swabs, contamination with blood and discharge. Lack of certified personnel available on the L&D floor to read the slides or the lab’s requirement to have the slides sent down to the lab.

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VAGINAL POOLING

VAGINAL POOLING          

Technique:

Visualization of an amniotic pool in the posterior fornix of the vagina

Accuracy:

Subjective

Drawbacks:

Speculum exam is required. Subjective. Urine, semen, and other fluids can easily be mistaken for amniotic fluid and vice versa.

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Ultrasound

:Technique

Ultrasound can detect oligohydramnios, suggesting loss of amniotic fluid due to membrane rupture

Accuracy:

Not a reliable screening test if used alone. Used only to help confirm diagnosis

Drawbacks:

Time-consuming. Requires equipment and expertise. Can only detect significant loss of amniotic fluid. Can’t confirm cause of fluid loss. Not all hospital facilities have ultrasound expertise easily accessible on a 24/7 basis.

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Amnio-Dye Infusion

Technique:

Instillation of dilute indigo carmine into the amniotic cavity and confirmation of rupture of membranes by documenting leakage of dye into the vagina (staining of tampon) within 20-30 minutes

Accuracy:

"Gold Standard" for diagnosis of rupture of membranes

Drawbacks:

Accurate, but highly invasive (requires amniocentesis). Expensive. Amniocentesis is associated with risk to pregnancy including bleeding, infection, latrogenic rupture of membranes, and loss of pregnancy (approximately 1 in 270).

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AMNISENSE

AMNIOTIC LEAK DETECTION KIT

Sensitivity: 95.76 Specificity:84.46

No invasive procedure require

A single drop of Amniotic fluid is enough for test

Maintain the comfort level of patient and doctors

  



Amniotic fluid Leakage

The amniotic fluid is that fluid surrounding the developing fetus that is found within the amniotic sac contained in the mother's womb.

Physical characteristics ;

pH of is around 7.2.

　

Specific gravity of 1.0069 – 1.008.

　

Volume depends on gestation , 400ml at mid pregnancy and reaches about 1000ml at 36-38 weeks .

High volume of amniotic fluid i.e. more than 2000 ml is called

Low volume of amniotic fluid i.e. less than 400 ml is called

Polyhydramnios. It results when the fetus does not swallow the usual amount of amniotic fluid e.g. in esophageal atresiaOligohydramnios. Renal agenesis (failure of kidney formation) is the main cause of oligohydramnios

Oligohydramnios.; It can develop at any stage in pregnancy , although it is more common in the last trimester especially in those women whose pregnancy extends beyond the 40 weeks since the amniotic fluid tends to decrease at that time.

Causes:

- it can also be caused by certain maternal conditions such as DM , high blood pressure.

Renal agenesis (failure of fetal kidney formation) is the main cause of oligohydramnios ,

　

                       Oligohydramnios.

The problems associated with oligohydramnios differ depending on the stage of the pregnancy.

Oligohydramnios is more likely to have serious consequences if it occurs in the first half of pregnancy than if it occurs in the last trimester. These consequences include :

Birth defects(too little amniotic fluid early in pregnancy can lead to compression of 　fetal organs, resulting in lung and limb defects)

Miscarriage

Premature birth

Still birth (due to compression of the umbilical cord).

- It is clear pale yellow fluid.