AMNIOTIC FLUID ANALYSIS – Purposes, Indications, General Instructions, Procedure, Factors Affecting Diagnostic Results, Nursing Implications, Client Teaching and Rare Complications (MATERNAL AND CHILD HEALTH NURSING)
Amniotic fluid analysis is useful for detecting chromosomal abnormalities, such as Down Syndrome or mongolism (trisomy 21); neural tube defects (spina bifida); and sex-linked disorders, such as hemophila; and for detecting fetal maturity. The amniotic fluid is obtained by amniocentesis. This procedure involves the insertion of a needle into the suprapubic area after the fetus has been located and manually elevated and the aspiration 5-15 ml of amniotic fluid
PURPOSES
- To detect chromosomal abnormalities, neutral tube defects and sex-linked disorders
- To determine fetal maturity
INDICATIONS
- Chromosomal disorders (e.g. down syndrome)
- Neural tube defects (e.g. spina bifida)
- Hemolytic disease due to Rh incompatibility
- Fetal sex (important for sex-linked disorders, e.g. hemophila)
- Fetal maturity
- Pulmonary maturity of the fetus (L/S ratio)
GENERAL INSTRUCTIONS
- Ultrasound may be used to locate the placenta and to determine fetal positions so that needle contact can be avoided
- Amniocentesis is performed during the 14th to 16th weeks of pregnancy. It usually is not done before the 16th week if a therapeutic abortion might be suggested
- Analyses of the amniotic fluid may also include color, bilirubin (present in the fluid until the 28th week but absent at full term), meconium (present during stress, e.g. in breech presentation), creatinine, lecithin/sphingomyelin (L/S) ratio (a decreased ratio can indicate respiratory distress syndrome), glucose, lipids and alpha-fetoprotein (AFP)
- Amnioscopy involves insertion of a fiberoptic lighted instrument (amnioscope) into the cervical canal to visualize the amniotic fluid. The color of a amniotic fluid can indicate fetal hypoxia. This test is normally performed close to full term, because it requires cervical dilatation. Because there is a risk of rupturing the amniotic membrane and of intrauterine infection, the test is rarely performed
PROCEDURE
- A consent form should signed
- Food and fluids are not restricted
- Have a client to void before the procedure to prevent puncturing the bladder and aspirating urine
- Cleanse the suprapubic area with an antiseptic such as povidone-iodine (betadine). A local anesthetic is injected at the site for amniocentesis
- The placenta and fetus should be located by ultrasound or manually (fetus only). A 22 gauge spinal needle with stylet is inserted through the skin to the amniotic cavity
- 5-15 ml amniotic fluid is aspirated. Apply a small dressing to the needle insertion site
- The procedure takes approximately 30 minutes
FACTORS AFFECTING DIAGNOSTIC RESULTS
A traumatic amniotic tap may produce blood in the amniotic fluid
NURSING IMPLICATIONS
- Recognize when amniocentesis for amniotic fluid analysis is indicated (e.g. with a familial history of sex-linked, genetic or chromosomal disorders; with a history of previous miscarriages; and in advanced maternal age (>35-years old). It is not a screening test
- Be supportive of the women and her partner. Be a good listener. Allow them time to ask questions and to express any concerns. Refer questions you cannot answer to the appropriate health professionals
- Be sure that the client urinates before the test and that the consent form is signed
CLIENT TEACHING
- Inform the client that normal results do not guarantee a normal infant, nor do they always predict sex correctly. The health care provider should tell the woman of potential risks
- Instruct the client to notify the healthcare provider immediately of any of the following; bleeding or leaking fluid from the vagina, abdominal pain or cramping, chills and fever or lack of fetal movement
- Encourage the women and her partner to seek genetic counseling especially if a chromosomal abnormality has been detected
RARE COMPLICATIONS
- Premature labor
- Spontaneous abortion
- Infection
- Fetal or placental bleeding
