Use of dexamethasone as antenatal therapy affects placentome microcirculation in goats? - Preliminary data

Antenatal therapy with corticosteroids have been widely established as standard protocol in women at high risk to premature birth, with the purpose to reduce respiratory distress syndrome in newborns (Bonanno et al., 2008. Am J Obst. 5:448-456). Small ruminants are often used as an experimental model for these studies with the aim of optimizing the dose and time of administration of these drugs (Morel et al., 2012. Theriogenology, 78:1763-1773). The aim of this study was to evaluate and compare the Doppler indices of arterial branches of placentome in pregnant goats submitted to different dexamethasone base protocols. Three protocols were tested: GI (n=4) goats received a single injection of 20mg/i.m at 139 day of gestation; GII (n=5) were given every 24h 2mg/i.m between 133 and 136 days, 4mg at 137 and 138 days and 20mg at 139 day; and GIII (n=5) were given 16mg/i.m every 12h at 139 and 140 days. All animals were submitted elective cesarean section to 141 days of pregnancy to obtain premature kids. Hemodynamic changes of two placentome were assessed by spectral Doppler ultrasonography (Mylabvet70®, ESAOTE, Genova, Italy). There was no difference between the different treatments for flow velocity integral (6.78±1.38, p>0.67), pulsatility index (1.61.69±0.68, p>0.21), resistive index (0.60±0.17, p>0.40); peak velocity (25.14±3.41, p>0.55), end diastolic velocity (11.26±1.93, p>0.86) and mean velocity (15.40±1.69, p> 0.36). In conclusion, the placentome microcirculation is not affected by the different doses or by corticosteroid administration time.