Sonographic biometrical normograms and estimation of fetal weight in the baboon (Papio anubis)

Background In order to consider the non-human primate as an adequate model for studying prenatal diagnosis and therapy, comparative data on fetal growth should be available. Methods Sixty ultrasound scans were performed in 22 baboons between 14 and 167 days of gestation. Measurements included greatest length, head circumference, biparietal diameter (BPD), transcerebellar diameter, abdominal circumference (AC), femur length (FL), and amniotic fluid index. For all parameters growth curves were established and compared with human curves. In 18 animals, birth weight and placental weight were determined. Different equations described in the literature for estimating the human fetal weight were tested in the baboon. Results The fetal and placental growth pattern in the baboon was comparable with humans. The best predictor of fetal weight was the formula presented by Combs: 0.23966 x AC(2) x FL + 1.623 x BPD(3). Conclusions A high similarity between baboon and human growth charts is shown. The best equation for estimating the baboon fetal weight is proposed