Amniocentesis. Flashcards
what are the diagnositic indications for amniocentesis ?
Early months (15–20 weeks): Genetic amniocentesis antenatal diagnosis of chromosomal and genetic disorders and neural tube defects Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Turner syndrome (monosomy X
Amniocentesis can detect infections via decreased glucose level, a Gram stain showing bacteria, or abnormal differential count of white blood cells
later
fetal maturity
Degree of fetal hemolysis in Rh-sensitized mother
Meconium staining of liquor
what are the therapeutic indications for amniocentesis ?
First half: (1) Induction of abortion by instillation of chemicals such as hypertonic saline, urea or prostaglandins. (2) Repeated decompression of the uterus in acute hydramnios.
Second half: (1) Decompression of uterus in unresponsive cases of chronic hydramnios . (2) intrauterine fetal transfusion in severe hemolysis following Rh isoimmunization. (3) Amnioinfusion: Oligohydramnios—(i) to prevent fetal lung hypoplasia, (ii) to minimize umbilical cord compression during labor.
B. to dilute meconium-stained amniotic fluid.
what is the procedure of amniocentesis ?
1) After emptying the bladder,
proposed site of puncture is infiltrated with lignocaine.
A gauge spinal needle with stylet is inserted into the amniotic cavity with US guidance.
The stilette is withdrawn.Initial 1–2 mL of fluid is either used for AFP or is discarded as it is contaminated with maternal cells. Rest is used for fetal karyotyping.
About 30 mL of fluid is collected in a test tube for diagnostic purposes.
Fetal cardiac motion is to be seen after the procedure.
Patient is asked to report for any uterine cramps, vaginal bleeding or leakage of liquor.
what are the prerequests in amniocentesis ?
Prior sonographic localization of placental position, fetal positioning and umbilical cord location.
It is also helpful in locating an amniotic fluid pocket that is not occupied by any fetal part,
Prophylactic administration of 100 mg of anti-D immunoglobulin in Rh-negative nonimmunized mother
normal stress test
what are the maternal complication?
Infection. (2) Hemorrhage (placental or uterine injury).
(3) Premature rupture of the membranes and premature labor
what are the fetal complications ?
Fetal loss (1 in 400 procedures)
Trauma. (3)
Fetomaternal hemorrhage. (4)
Oligohydramnios due to leakage of amniotic fluid and that may lead to: (i) Fetal lung hypoplasia. (ii) Respiratory distress.
why is early amniocentesis such as 11-14 weeks avoided
not done for genetic indications as the cell culture failure rate is high. Less fluid is withdrawn. Rates of complications are high.
contraindication of amniocentesis
no reassuring NST
HIV-positive women a
Amniocentesis is the best diagnostic if done
16–18 weeks
