Missed abortions and still-births can be studied by karyotyping and FISH to detect chromosomal abnormalities. A high frequency of chromosome aneuploidy is found in spontaneous abortions. Aneuploidy detection by FISH can include combinations of chromosomes 13, 21 / 18, X, Y / 16 / 22.

Karyotyping from ‘products of conception’ (POC) of a spontaneous or missed
abortion is done by fibroblast culture to rule out a chromosome abnormality,
which is a likely cause of the abortion. To avoid contamination of tissue, the
sample from early abortions should be taken directly in a sterile Menstrual
Regulation (MR) syringe and transported in a sterile container with normal
saline to which 2-3 drops of sodium heparin and Gentamycin are added. The sac
surrounded by chorionic villi is the tissue of choice in early abortions while a
1” piece of placenta and fetal skin should be collected from 2nd and 3rd
trimester abortions. Cord blood (0.5-1ml) should also be collected in sodium
heparin vaccutainers whenever possible, from 3rd trimester abortions. The
samples can be stored in the refrigerator overnight if required, before
transportation at room temperature. Samples should never be put into formalin
for karyotyping or FISH. Incase karyotyping fails in our laboratory due to
contamination, FISH for chromosomes 13, 18, 21, X and Y is carried out at no
extra cost. We also accept back-up samples of chorionic villi stored in Carnoy’s
fixative from other laboratories, for FISH.