USE OF ULTRASOUND TO MONITOR PRENATAL GROWTH AND DEVELOPMENT IN THE COMMON MARMOSET (CALLITHRIX-JACCHUS)

The increasing use of non-human primates to study fetal development an d neonatal management has necessitated the availability of fetuses of known gestational history. In this study, prenatal development and gro wth were investigated in the common marmoset (Callithrix: jacchus) usi ng ultrasound. The objectives of this study were: (1) to determine the accuracy of ultrasound for monitoring prenatal growth and development in common marmosets, (2) to determine if litter size influences prena tal growth trajectories, and (3) to assess growth discordancy among li tter mates. Fifty pregnancies were monitored longitudinally using real -time abdominal sonography. During each examination the number of fetu ses was recorded, and crown-rump length (CRL) and biparietal diameter (BPD) were measured. The results indicate that ultrasound is a reliabl e method for observation of gross morphological changes during prenata l development in this species. Measures of CRL and BPD taken early in gestation using ultrasound were in agreement with those from gross spe cimens. Triplets were significantly (P < 0.05) smaller than twins for both BPD and CRL. No significant relationship was found between litter size and within litter variation in CRL or BPD. This study is the fir st longitudinal investigation of prenatal growth and development in C. jacchus. The observations from this study will be of use for determin ing approximate gestational age of fetuses, as well as providing guide lines for routine monitoring of pregnancy in this species. (C) 1995 Wi ley-Liss, Inc.