Percutaneous Umbilical Cord Blood Sampling

Introduction

Percutaneous Umbilical Blood Sampling (PUBS) is a pre-natal diagnostic procedure performed during the second trimester (between week 18 to 22) where doctor extract a sample of fetal blood from the vein in the umbilical cord via a fine needle through the abdomen of the mother. The extracted blood can then be used to detect certain anomalies such as chromosome abnormalities such as Down syndrome, Blood Disorders such as Anaemia and certain infections, growth retardation, some birth defects as well as some metabolic disorders. PUBS is usually used when other diagnostic test such as Ultrasound, Amniocentesis, Chorionic Villus Sampling do not yield conclusive result requiring further testing. This pre-natal diagnostic technique is also used to deliver certain therapies such as the administration of medicine and transfusion of blood directly to the fetus.

Percutaneous Umbilical Blood Sampling (PUBS) is an invasive procedure and although it is a very useful technique in diagnosing several complications it has a long list of potential side effects such as blood loss from the puncture and premature rupture of the membranes. Miscarriage may also occur with the chance of this occurring is 1 to 2 times out of every 100 procedures.

Yet the benefits of PUBS as opposed to other pre-natal diagnostic techniques such as Amniocentesis or Chorionic Villus Sampling (CVS) is that genetic information also known as Karyotypes is available much sooner after the procedure.

Procedure

Draft Procedure 1

Percutaneous Umbilical Cord Sampling (PUBS) uses an advanced imaging ultrasound to determine the location of where the Umbilical Cord meets the placenta or in other words inserts into the placenta. This ultrasound image the helps a doctor guide a thin needle through the abdomen and uterine wall of the mother and into the Umbilical Cord. This needle is actually inserted into the Umbilical Cord and retrieves a small amount or sample of fetal blood. This blood is the sent off to a lab for analysis and usually within 72 hours of doing procedure results are available.

Draft Procedure 2

Percutaneous Umbilical Cord Sampling (PUBS) can be simplified into three main parts.

Part 1

An advanced imaging ultrasound is used by doctor to determine or in other words pin point the location of where the umbilical cord inserts into the placenta. This ultrasound image then helps the doctor doing the procedure guide a thin needle through the abdomen and uterine wall of the mother and into the umbilical cord more precisely into the umbilical vein running through the cord. The needle is inserted into the cord to receive a small sample of Fetal Blood.

Part 2

There are two main routes for the actual retrieval of fetal blood. The method the doctor uses to perform the procedure is determined by the Placenta’s positions in the uterus and point of connection to the umbilical cord. If the Placenta is attached towards the front of the uterus known as Placenta Anterior, the doctor will insert the needle straight into the umbilical cord surpassing the amniotic sac. The Amniotic Sac is a fluid – filled structures that surrounds the developing fetus acting as a cushion thus protecting it.

If the placenta is attached towards the back of the uterus known as Placenta Posterior, the needle must travel through the amniotic sac to reach the umbilical cord. This may cause some temporary bleeding and cramps. It is also important to notice that at the time of performing cordocentesis if the mother is Rh – negative unsensitised she should receive Rh Immune Globulin (RhIG).

Part 3

After the Fetal Blood sample is drawn the sample is sent to the lab where a technician tests the blood for any genetic defects and other disorders. The results for the test are usually available with 72 hours yet in some circumstances it may take a few weeks to receive the results. If a problem is diagnosed the doctor will explain the result giving information about best care for the baby or in more extreme cases ending the pregnancy.

--Mark Hill 01:43, 5 August 2010 (UTC) You can now put your group discussion here. Here is the code to set up a search of PubMed Books - Prenatal Diagnosis and to Search Pubmed Now - Prenatal Diagnosis

References

2010 ANAT2341 Group Projects

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Cite this page: Hill, M.A. (2024, May 2) Embryology 2010 Group Project 4. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_Group_Project_4

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