The yield and complications of amniocentesis performed after 24 weeks of gestation.

PURPOSE: This study assessed the use and complications of late amniocentesis (AC) and analyzed factors that affect complication rate. METHODS: A retrospective analysis of 167 genetic AC performed after 24 weeks during a 10-year period in two medical centers was conducted. Data regarding the indications for AC, genetic work-up, and pregnancy outcomes were retrieved from patient medical records and telephone-based questionnaires. RESULTS: Mean gestational age (GA) at the time of AC was 31.7 ± 2.7 weeks; 104 procedures were performed at ≤32 weeks, including 24 at ≤30 weeks. The overall pregnancy complication rate occurring at any time after the procedure was 6.6% (11). Of these, 4.8% (8) occurred within a month after AC, including 2.4% (4) that occurred within a week. An additional three occurred after 30 days. There were no differences in the total complication rate and in the rate of specific complications of procedures performed at ≤32 weeks or at ≤30 weeks. Maternal age did not affect outcomes. Genetic testing was abnormal in five cases (3%). Amniocyte culture failed in 3 cases (2.3%), with no technical failures in 52 chromosomal microarray tests. CONCLUSION: The complication rate of AC performed after 24 weeks was 4.8%, which is significantly higher than that of second trimester AC. GA and maternal age did not affect the complication rate.

Identification of the fetal hippocampus and fornix and role of 3-dimensional sonography.

OBJECTIVES: The purposes of this study were to identify the fetal hippocampus and fornix using 3-dimensional sonography, to measure their curved length during pregnancy, and to describe a systematic method for volume data set analysis of the fetal hippocampus and fornix. METHODS: Three-dimensional volumes of the fetal brain were acquired prospectively in 34 patients between 14 and 37 weeks' gestation. Volumes were acquired with trans-abdominal and transvaginal transducers. All volumes were analyzed offline by 2 examiners separately. The feasibility of identifying the fetal hippocampus and fornix was analyzed. The curved length of the hippocampus-fornix structure was measured on the right and left hemispheres. RESULTS: The fetal hippocampus and fornix were identified bilaterally in 32 of 34 fetuses (94%) at gestational ages of 14 weeks 5 days to 37 weeks 1 day (mean, 23 weeks 3 days). In 1 fetus (3%), only one side was shown, and in another fetus (3%), both sides were obscured by acoustic shadows. A systematic approach for identification of the fetal hippocampus is described. Linear growth of the fetal hippocampus and fornix was shown during pregnancy and was correlated with both the gestational week and the head circumference (R = 0.71 and 0.74, respectively; P = .01). The length of the hippocampus and fornix did not differ between the left and the right hemispheres (P = .598). CONCLUSIONS: The fetal hippocampus and fornix can be identified by a systematic analysis of 3-dimensional data set volumes. The normal hippocampus and fornix show linear growth throughout pregnancy.