Cordocentesis is a method of fetal blood sampling which is usually carried out under ultrasound guidance.
It may be performed for various reasons which include:
- establish the degree of a fetal anaemia
- further investigation of an underlying chromosomal anomaly
- further investigation of in utero infection
Usually a 20-gauge spinal needle is inserted under direct sonographic guidance towards the umbilical vein. The site of cord insertion is at the placenta where the cord is relatively fixed is generally fixed. The presence of a posterior placenta increases the difficulty of the procedure and in such cases, a muscle relaxant may be required prior to the procedure to immobilise the intervening foetus.
There is a higher complication rate if performed prior to 20 weeks. An associated foetal loss rate as high as 4% has been reported 2.
Recognised complications include:
- 1. A Cameron et.al Fetal Medicine for the MRCOG and Beyond. RCOG Press. ISBN:1906985367. Read it at Google Books - Find it at Amazon
- 2. Maulik D. Doppler ultrasound in obstetrics and gynecology. Springer Verlag. (2005) ISBN:3540230882. Read it at Google Books - Find it at Amazon
- 3. Srisupundit K, Wanapirak C, Piyamongkol W et-al. Comparisons of outcomes after cordocentesis at mid-pregnancy between singleton and twin pregnancies. 2011;doi:10.1002/pd.2834 - Pubmed citation
- 4. Tangshewinsirikul C, Wanapirak C, Piyamongkol W et-al. Effect of cord puncture site in cordocentesis at mid-pregnancy on pregnancy outcomes. 2011;doi:10.1002/pd.2790 - Pubmed citation
- 5. Tongsong T, Wanapirak C, Kunavikatikul C et-al. Cordocentesis at 16-24 weeks of gestation: experience of 1,320 cases. Prenat. Diagn. 2000;20 (3): 224-8. Prenat. Diagn. (link) - Pubmed citation