Fetal growth in the baboon during the second half of pregnancy

The normal growth profile of critical fetal organs through the last third o f gestation has not been documented in detail in human fetuses or the fetus of any nonhuman primate species. Recent epidemiological studies in human p regnancy suggest that fetal growth plays a major role in the programming of life-long health by modifying cardiovascular, pancreatic, brain, and liver growth. The present study aimed to produce a detailed database of individu al organ growth in the fetal baboon in late gestation. Fetal organ weights were obtained from 43 baboon fetuses between 121 and 177 days of gestation. Various organs (brain, heart, kidney, femur, intestines, and spinal cord) showed no sign of slowed growth in late gestation while growth of others (l ung, liver, stomach, and bladder) accelerated in late gestation. The fetal adrenal and thymus showed a decrease in growth rate over the final 20 and 1 0 days of gestation respectively. These observations provide a database tha t will permit analysis of factors responsible for regulation of normal and altered fetal organ development in this important experimental species.