Spontaneous abortion after amniocentesis in women with a history of spontaneous abortion.

The incidence of spontaneous abortion after amniocentesis (19 to 28 weeks gestation) in women who have had previous spontaneous abortions is compared with the rate in women who have not had previous spontaneous abortions. The outcome of the pregnancy after amniocentesis and the previous history of spontaneous abortion is reported for 691 pregnancies. The rate of spontaneous abortion after amniocentesis was found to be significantly higher in women who had one or more previous spontaneous abortions, 12/238 (5 per cent), than in women who did not, 6/453 (1.3 per cent). In women who reported two or more previous spontaneous abortions, the rate was 7/81 (8.6 per cent). No statistically significant effect of maternal age or gravidity was detected. The incidence of spontaneous abortion after amniocentesis was greater in the three weeks following the procedure (three for each of the three weeks) than in the subsequent seven weeks (nine for seven weeks).

A computer method for determining plaque size and plaque morphology.

We describe a computer method for determining plaque size and morphology from photographs of hemolytic plaques. The method eliminates any inter-measurer and intra-measurer inconsistencies that may arise when manual measurements are made on plaques whose boundaries are poorly defined. For circular plaques inner and outer plaque radii are determined. In addition the computer generates a density profile for each plaque, i.e., a plot of the film density versus the radial distance from the antibody forming cell. We demonstrate the use of the method by analyzing a time study of the growth of a single plaque.