Fetoplacental Unit Ultrasonography and Immunoreactive Steroid Concentrations in Jennies Experiencing Late-Term Pregnancy Loss

This study aimed to compare ultrasonographic features and steroid concentrations of jennies undergoing late-term pregnancy loss (n = 5) with gestationally age-matched health controls (n = 5). Transrectal ultrasonography of the combined thickness of uterus and placenta (CTUP) and fetal eyeball diameter was carried out at 15-day-intervals. Fetal heartbeat, aortic, and thorax diameters were determined by transabdominal ultrasonography at 30-day-intervals. Blood samples were collected simultaneous with each transrectal ultrasonography to determine progestogen and estradiol concentrations. Data were assessed for normality with Shapiro-Wilks. Data were log-transformed and analyzed with a mix model. Non-normally distributed data were analyzed with Kruskal-Wallis. Post-hoc analyzes were performed with Sidák's or Dunn's tests based on distribution. Gestational length between groups was compared with a t-test. Statistical significance was set at P < .05. The gestational length was shorter in jennies experiencing pregnancy loss (345 ± 32.3 vs. 365.4 ± 10.4 d P = .0009). Increasing gestational age (P < .0001) and pregnancy loss group (P = .004) had greater CTUP measurements with an interaction between them (P = .01). Fetal eyeball diameter increased with gestational age (P < .0001) but did not vary with group (P = .26), and there was no interaction between gestational age and group (P = .71). Fetal aortic and thorax diameters increased with gestational age (P < .0001), but an interaction between gestational age and group was only present with thorax diameter (P = .01). No effect of group was found for aortic (P = .78) or thorax (P = .86) diameters. Group (P = .06) and gestational age (P = .07) tended to be associated with an increased fetal heartbeat, but there was no interaction between them (P = .98). There was no effect of gestational age (P = .31), group (P = .19), or interaction between them for progestogens concentrations (P = .21). Estradiol concentration was not affected by gestational age (P = .76) or group (P = .51). In conclusion, late-term pregnancy loss was associated with increased CTUP measurements in donkeys.