TRANSVAGINAL ULTRASONOGRAPHIC (TVS) EVALUATION OF BABOON GESTATION FROM 37-62 DAYS POSTCONCEPTION

Our objective was to determine the growth of the embryo and surroundin g structures during baboon (Papio anubis) gestation using transvaginal sonography (TVS). To this end, we evaluated 19 timed-mated baboons us ing TVS between 37 and 62 days of gestation. After visualization of th e gestational sac, amniotic sac, and yolk sac, the three largest diame ters of each of these extra embryonic structures were measured using l ongitudinal and transverse views. Embryonic crown-rump length (CRL) wa s also recorded. Embryonic heart rates were determined using the M-mod e function of the ultrasound equipment. All 19 gestations developed wi thout complications. No significant trend could be demonstrated for he art rate or yolk sac diameters over the 37-62 day gestational age peri od. Mean (SD) gestational age in days, heart rate, and yolk sac diamet er, respectively, for the group were 48 (7.8) days (range: 37-61), 180 (15) beats per minute (range: 156-221) and 5 (0.1) mm (range: 3-8). S ignificant correlations (P < 0.0001) were determined between gestation al age and CRL and gestational and amniotic sacs. We conclude that TVS allows a clear visualization of the embryo proper and all the cavitie s within the gestational sac of the baboon gestation. This study has d etermined the normal pattern of changes of these cavities from 37-62 d ays of gestation. Future applications of these findings may include sa mpling fluid from these cavities for biochemical, cytological, and met abolic studies. (C) 1997 Wiley-Liss, Inc.