Evaluation of amniocentesis guided by real-time ultrasonic tomography.

The purpose of this study was to evaluated the success rate and safety of amniocentesis guided by real-time ultrasonic tomography. Two hundred and fifty amniocenteses were done on pregnant Japanese women of various gestational ages at Kyushu University Hospital from October 1978 to July 1981. These amniocenteses were dependent on the following definite indications: risk of chromosomal disorder 160 (64%), diagnosis of congenital malformation 37 (14.8%), estimation of fetal maturation 37 (14.8%), and Rh isoimmunization 16 (6.4%). Results were as follows: 1. Amniotic fluid was successfully collected 246 times (98.4%). There were 4 failures (91.6%), all associated with oligohydramnios in the third trimester. Of the successful tappings, 215 (87.4%) were single taps. The other cases required two or three taps. No significant difference was found between the success rate of single tappings done in the first, second, and third trimester. 2. Blood-stained amniotic fluid was obtained from 13 subjects (5.3%). In five cases, the placenta had been penetrated by the needle. The incidence of bloody taps was significantly higher for cases of transplacental tapping (5/28) than for those of decidual puncture (9/222). 3. In 16 subjects, immediately after removal of the puncture needle, bleeding from the uterine wall or the placenta was observed as falling droplets in the picture on the scope. In the transplacental tappings, such bleeding continued for longer than 60 seconds, and in the other tappings no longer than 120 seconds.