If oligohydramnios, growth retardation or foetal malformations are demonstrated by ultrasonic scanning in the second or third trimesters, this implies that the risk of chromosome anomalies is significantly increased. In cases such as these, determination of the foetal karyotype may therefore be indicated. Until recently, amniocentesis has been employed for this but the results of the chromosome investigation are not available until two to three weeks after the intervention. The delay between amniocentesis and the result of chromosome investigation imposes a mental strain on the pregnant woman. Three patients with abnormal ultrasonic findings in the second trimester were, therefore, submitted to transabdominal chorion villus biopsy and, in all three cases, a karyotype was available within 48 hours. Chorion villus biopsy in the second (and third) trimester is indicated in pregnancies in which oligohydramnios, growth retardation or foetal malformations have been demonstrated by ultrasonic scanning, in cases where referral for antenatal diagnosis is very late and when chromosome investigation after amniocentesis proves unsuccessful and repeated amniocentesis would result in an unacceptably late result.
Ugeskrift for Laeger, 1990, Vol 152, Issue 1, p. 28-30