Placental biopsy for rapid fetal karyotyping in the second and third trimesters of pregnancy.

Rapid chromosomal analysis in the 2nd and 3rd trimester of gestation is desirable in cases of suspected or proven fetal malformation. The presence of any chromosomal aberration of the fetus influences the further prenatal and perinatal management of the pregnancy. Placental biopsy and preparation of trophoblast tissue after short term culture offers the possibility of getting satisfactory results within 2 to 3 days of biopsy. Fifty-seven patients underwent placental biopsy between the 16th and 36th weeks of gestation because of sonographically suspected or proven fetal malformation. In 51 of 57 cases fetal karyotyping was successful and no severe complications after biopsy were seen. Eight pathologic karyotypes were found. In 3 cases the chromosomal analysis yielded unsatisfactory results because of the inadequate quality of metaphases. In another 3 cases not enough chorionic tissue was aspirated in 2 biopsy attempts. In all other cases normal fetal karyotypes were found. Sonographically guided placental biopsy represents a simple method for fetal karyotyping and is a useful tool for the management of pregnancies with suspected or proven fetal malformation in the 2nd and 3rd trimester.