Transabdominal placental biopsy in the second and third trimester of pregnancy.

Transabdominal placental biopsy under ultrasound guidance was carried out in 260 cases in the second trimester and 50 cases in the third trimester of pregnancy. Placental tissue was aspirated using an 18 or 20 gauge needle. In a total of 310 placental biopsies in the second and third trimester, 100 were performed because of suspicious ultrasonographic findings. Placental biopsy is simple in the presence of severe oligohydramnios where fetal blood sampling is usually more difficult. Oligohydramnios and polyhydramnios were the ultrasonographic findings in 50% of cases and were found to be associated with 30% of abnormal chromosomal findings. There was one (0.3%) abortion within two weeks following placental biopsy. Placental biopsy did not affect the outcome of the pregnancy.