BLOOD CONTAMINATION OF AMNIOTIC FLUID DURING AMNIOCENTESIS - INCIDENT, ACCIDENT OR COMPLICATION.

Amniocentesis is the most commonly performed invasive prenatal diagnostic procedure. The relative simplicity of the method has made amniocentesis available in a large number of centres. Amniocentesis may increase the risk of fetomaternal hemorrhage (FMH) due to needle transfixation of the maternal abdomen skin to the amniotic membrane and sometimes the placenta. There is an increase in FMH after performing amniocentesis, but there is no consensus regarding the best method to monitor the safety of these procedure. Flow cytometry immunophenotyping, using a monoclonal antibody against fetal hemoglobin, has become an interesting alternative to classical Kleihauer test to measuring FMH. Blood contamination of amniotic fluid (AF) during amniocentesis correlates directly with: needle thickness, physician experience, number of puncture points taken for sample acquisition, placental location. The puncture needle is recommended to have a thickness between 20-23 gauge (G).. Maternal cell contamination is prevented by discharging the first 2 ml of each sample. Another factor affecting safety of amniocentesis is the volume of procedures performed by the operator. High volume experience is reported to have decisive impact on rates of procedure-related adverse outcomes The impossibility of AF extraction at the first puncture requires its repetition, which increases the risk of AF contamination. From this point of view, it is extremely important to identify before the procedure the most voluminous AF bags, but also to choose a tract that avoids the transplacental passage. Placement of the placenta on the anterior wall increases the risk of AF contamination compared to the back or posterior wall location. Regarding the isoimunisation risc after amniocentesis, when a FMH occurs with less than 0.1 ml, isoimmunization at six months after delivery is 3%. Amniocentesis is safe to be carried out in fetal medicine when is followed by standard methods and conducted by trained professionals. [ABSTRACT FROM AUTHOR]