Invasive Procedures
Invasive prenatal procedures involve probes or needles being inserted into the uterus (approximately from 16th to 20th weeks of gestation and CVS (chorionic villus sampling), which can be done earlier (between 9.5 and 12.5 weeks of gestation).
A comparative study shows no significant difference in total pregnancy loss between transabdominal CVS and second trimester amniocentesis.