Clinical and laboratory experience of chorionic villous sampling in Nigeria

Abstract

Background: Chorionic villous sampling is a first trimester invasive  diagnosis procedure that was introduced in Nigeria <2 decades ago.
Objective: The objective of the following study is to review experience with chorionic villous sampling in relation to clinical and laboratory procedures, including general characteristics of women, indications and outcome, complications, laboratory analysis and learning curve.
Materials and Methods: Descriptive study of chorionic villous samplings between 2005 and 2012. Clinical and laboratory data were extracted from records. The women had trans.abdominal or trans-cervical procedure after counseling. Deoxyribonucleic acid extraction was by boiling method and molecular diagnosis by restriction fragment length polymorphism or quantitative fluorescence polymerase chain reaction. Analyzed data were presented using simple frequency tables.
Results: A total of 426 women were analyzed. The major indications were Sickle cell anemia (97.2%), gender determination (1.9%) and aneuploidy (0.7%) respectively. Most procedures (71.2%) were done between 11+0 and 13+6 weeks by trans.abdominal approach (88.7%). Overall success at the first sampling was 98.8%. Error in laboratory diagnosis recorded in 3 (0.7%) pregnancies, while 5 (1.2%) were reanalyzed due to maternal decidua/inadequate fetal sample (0.7%) or failure of amplification (0.5%) respectively. Primary sex ratio was 5 (XY): 3 (XX). Down syndrome was
the most common aneuploidy diagnosed with a detection rate of 66.7%. Learning curve was evident from reducing the incidence of abortion, number of aspirations and increasing success at the first attempt and villi yield.
Conclusion: The present study shows acceptance and utilization of chorionic villus sampling and also demonstrates its safety and reliability.

Key words: Chorionic villous sampling, clinical, down syndrome, laboratory, sickle cell disease