Ultrasound-guided cardiac blood sampling of the rabbit fetus

The object of the study was to determine whether cardiac sampling of the rabbit fetus could be successfully accomplished with minimal procedure-related loss. Pregnant rabbit dams were randomized to undergo ultrasound-guided fetal cardiac sampling in either the left or right uterine horn at 27 days of gestation; cesarean delivery was performed the following day. Liveborn pups from unsampled uterine horns underwent cardiac puncture immediately after birth. Fetal hematologic parameters were then compared to neonatal parameters. The acute fetal mortality from the sampled uterine horns was similar to that of the unsampled horns (3.6 vs. 4.5%). Fetal hematologic values were significantly higher than neonatal values with the exception of the reticulocyte count. This rabbit model offers a new approach for the evaluation of novel treatment modalities for hemolytic disease of the human fetus.