Gestational ultrasonography and Dopplerfluxometry in capuchin monkeys (Sapajus apella) zoometric

Abstract

The objectives of the current study were as follows: 1) to evaluate blood flow in the uterine (UA) and umbilical (Uma) arteries in pregnant capuchin monkeys by measuring the resistive index (RI) and pulsatility index (PI); 2) to determine the presence or absence of the early diastolic notch and diastolic flow in the UA and Uma flow waveforms, respectively; 3) to perform conceptus echobiometry for fetal growth assessment during pregnancy; 4) to describe the moment that the fetal organs were initially observed; and 5) to determine when the diagnosis of fetal gender is possible. Seven healthy, sexually mature female Sapajus apella were examined in Weeks -20 to -1 before whelping (whelping Week 0). Triplex Doppler was used to assess the blood flow and fetal heart rate, and B-mode ultrasonography was used to assess the fetal organs and conceptus measurements, including the gestational sac latero-lateral longitudinal (LLL) and latero-lateral transversal (LLT), the crown rump length (CRL), biparietal diameter (BPD), occipito-frontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and fetal organ. All the pregnancies ended with a normal whelping and the birth of a live newborn. Prior to whelping, all conceptus dimensions increased significantly, whereas the RI and PI of both the UA and Uma decreased significantly. For the UA, the RI and PI were (mean ± SEM) 0.835 ± 0.017 and 2.157 ± 0.129, 0.808 ± 0.008 and 1.920 ± 0.041, and 0.761 ± 0.006 and 1.759 ± 0.036 on periods -3, -2 and -1, respectively. For the Uma, the RI and PI were 0.97 ± 0.01 and 2.50 ± 0.02 at Week -17 and were 0.64 ± 0.02 and 0.98 ± 0.04 at Week -1, respectively. The complete disappearance of the early diastolic notch in the UA, and the complete appearance of diastolic flow in the Uma occurred on Week -1 and Week -11, respectively. Linear regression analyses regarding the relationship of the weeks before whelping (WBW) with the conceptus parameters were as follows: CRL = 16.93 + 0.93 WBW and FL = 3.62 + 0.22 WBW (R² = 0.98, P < 0.0001); AC = 13.46 + 0.67 WBW (R² = 0.96, P < 0.0001); BPD = 4.46 + 0.20 WBW (R² = 0.95, P < 0.0001); LLL = 11.46 + 0.45 WBW, LLT = 9.52 + 0.38 WBW and HC = 16.68 + 0.80 WBW (R² = 0.92, P < 0.0001); Uma RI = 0.64-0.02 WBW and PI = 0.79-0.11 WBW (R² = 0.90, P < 0.0001); and OFD = 5.84 + 0.27 WBW (R² = 0.86, P < 0.0001). The authors concluded that for fetal echobiometry UA and Uma perfusion were important endpoints to assess fetal vitality in the capuchin monkey. Moreover, it was possible to describe the moment when the organs were visualized and perform sexing.

Keywords: Blood flow; Fetal development; Fetal sexing; Organogenesis; Ultrasonography.