Definition
Amniocentesis is the deliberate puncture of the amniotic sac per abdomen for diagnostic and therapeutic purposes.
Description
Amniocentesis is a procedure needing informed consent, in which amniotic fluid is removed from the uterine cavity by inserting a needle through the abdomen and uterine walls into the amniotic sac. The normal time for the procedure is between 16 and 18 weeks’ gestation, when approximately 20 mL of amniotic fluid is removed and sent for analysis.
Indications
- Diagnostic:
- Early months (14-16 weeks):
- Diagnosis of chromosomal and genetic disorders.
- Sex-linked disorders.
- Karyotyping.
- Inborn errors of metabolism.
- Neural tube defects.
- Later months:
- Fetal maturity.
- Degree of fetal haemolysis in Rh-sensitized mother.
- Meconium staining of liquor.
- Amniography or fetography.
2. Therapeutic:
- First-half of pregnancy:
- Induction of abortion by instillation of chemicals, such as hypertonic saline, urea or prostaglandin.
- Decompression of the uterus in acute hydramnios.
- Second half of pregnancy:
- Decompression of uterus in unresponsive cases of chronic hydramnios.
- To give intrauterine fetal transfusion in severe haemolysis following Rh isoimmunization.
- Amnioinfusion:
- Infusion of warm normal saline into the amniotic cavity, transabdominally or trans cervically increase the volume of amniotic fluid.
Preprocedural preparations
- Obtain informed consent.
- Ensure that ultrasonogram is done for sonographic localization of placenta to prevent bloody tap and fetomaternal bleeding.
- Prophylactic administration of 100 mg of anti-D immunoglobulin in Rh negative nonimmunized mother.
- Ask patient to empty her bladder.
- Skin preparation is needed on the day of procedure.
- Obtain maternal vital signs and a 20-minute FHR tracing to serve as baseline.
Articles and equipment needed
TPR tray
- Stethoscope.
- Sterile gloves.
- Dressing tray.
- Sterile towels-4.
- 1% lignocaine.
- Disposable syringes-5 mL and 20 mL.
- Cotton swabs.
- Antiseptic solutions.
- Sterile bottles – to collect the specimen.
- 20-22 gauge spinal needle of 4-inch length with stylet.
- Adhesive plaster.
Procedure
| Nursing actions | Rationale | |
| 1. | Before procedure Explain to patient the need/purpose of procedure and how it will be done. | Minimizes anxiety and facilitates patient’s cooperation. |
| 2. | Ensure that informed consent is signed. | Ensures full awareness of procedure for patient and protects the health care professionals. |
| 3. | Have the woman empty her bladder, if the fetus is more than 20 weeks gestation (If the fetus is less than 20 weeks gestation, the woman’s full bladder will hold the uterus steady and out of the pelvis). | Avoids injury to the woman’s bladder. |
| 4. | Assemble equipment. | Promotes organization and saves time and effort. |
| 5. | Provide privacy. | Reduces anxiety. |
| 6. | Assist patient to lie in dorsal position. | Exposes the area of puncture. |
| 7. | Check the maternal vital signs and FHR. | Obtains baseline data. |
| 8. | During procedure Wash hands and don sterile gloves. | Reduces risk of transmission of microorganisms and maintains surgical asepsis. |
| 9. | Start IV fluids in accordance with institutional policy. | |
| 10. | Administer terbutaline SC or IV or ritodrine IV per institutional policy. | Reduces chances of uterine contractions during and after the procedure. |
| 11. | An ultrasound examination is performed and the placenta localized, and a pool of liquor found. | Reduces the possibility of bloody tap and abortive attempts and reduces risk of complications. |
| 12. | Drape the area with sterile towels. | Prevents unnecessary exposure. |
| 13. | Prepare abdominal wall aseptically. | Reduces the risk of pathogens entering the skin through the puncture site. |
| 14. | Assist the physician in infiltrating the proposed site of puncture with 2 mL of 1% lignocaine. | Causes loss of painful sensation in the area. |
| 15. | Ensure adequate time between infiltration of local anesthetic and introduction of needle into the amniotic sac. | Reduces pain and discomfort related to the procedure. |
| 16. | Assist physician while inserting the needle and stilette (A 20–22-gauge spinal needle about 4-inch length) through the abdominal wall into the uterus, under direct ultrasound guidance. The stilette is then withdrawn and a few drops of liquor are discarded. | A suitable pool of liquor is identified by ultrasound. First 2 ml may be contaminated by maternal cells or blood and should be discarded. |
| 17. | Physician withdraws 10-20 mL of amniotic fluid for analysis or a smaller amount if the amniocentesis is performed in the first trimester. | Serves for analysis of the amniotic fluid for fetal normalcy. |
| 18. | As physician withdraws the needle, keep a dressing gauze and place an adhesive bandage over the puncture site. | Minimizes tissue damage and discomfort to patient. |
| 19. | Monitor the woman during the procedure for signs of premature labor, bleeding or fetal distress. | Facilitates early detection of maternal/fetal complications. |
| 20. | Discard the used materials. | Prevents spread of microorganisms. |
| 21. | After procedure Remove and discard the gloves. | Prevents spread of microorganisms. |
| 22. | Wash hands. | Prevent cross infection. |
| 23. | Replace the articles in the utility room. | |
| 24. | Obtain maternal vital signs and a 20-minute fetal heart tracing. | Serves as a baseline to evaluate possible complications. |
| 25. | Instruct the woman to report signs of bleeding, unusual fetal activity, abdominal pain, cramping, or fever while at home after the procedure. | Identifies early signs of complications. |
| 26. | Label the specimen container adequately, including the estimated weeks of gestation and EDD. Send the specimen to laboratory for investigation immediately. | Ensure proper identification of the specimen and reporting of the findings. |
| 27. | Record the procedure done, date, time, name of physician who performed the test, maternal and fetal responses and details of specimen taken. | Provides for accurate documentation of procedure. |
Complications
Maternal
- Infection.
- Antepartum haemorrhage.
- Rh isoimmunization.
- Fetal loss.
- Abortion.
- Preterm labor.
- Amniotic fluid leakage.
Foetal
- Haemorrhage.
- Trauma to umbilical cord and vessels.
- Fetal trauma resulting from needle puncture.
- Death.
Special considerations
Colour of amniotic fluid indicates condition of fetus:
- Opaque with greenish brown discoloration-meconium in the amniotic fluid.
- Yellow with slight turbidity-hemolytic diseases of the newborn.
- Opaque with dark red blood in the amniotic fluid.
- Opaque with yellow brown (tobacco juice)-intrauterine death.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwer’s, ISBN-13:978-9388313285
- Annamma Jacob, Manual of Midwifery and Gynaecological Nursing, 4th Edition, 2023, Jaypee Publishers, ISBN: 978-9356961593
- Adrianne Dill Linton, Medical-Surgical Nursing, 8th Edition, 2023, Elsevier Publications, ISBN: 978-0323826716
- Donna Ignatavicius, Medical-Surgical Nursing: Concepts for Clinical Judgment and Collaborative Care, 11th Edition ,2024, Elsevier Publications, ISBN: 978-0323878265
- Lewis’s Medical-Surgical Nursing, 12th Edition,2024, Elsevier Publications, ISBN: 978-0323789615
- AACN Essentials of Critical Care Nursing, 5th Ed. Sarah. Delgado, 2023, Published by American Association of Critical-Care Nurses ISBN: 978-1264269884
- Ernstmeyer K, Christman E, editors. Nursing Fundamentals [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2024. PART IV, NURSING PROCESS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK610818/
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