Continuous deep intravenous infusion in rabbit embryotoxicity studies

1. This investigation was undertaken to evaluate the suitability of an intravenous infusion technique in the pregnant rabbit. 2. 18 New Zealand White rabbits were anaesthetised on day 1 of gestation and an indwelling catheter was implanted into the superior vena cava by introduction into the jugular vein. The catheter was attached by a tether system to a remote infusion pump. 3. The pregnant rabbits were infused with physiological saline at a rate of 4 ml kg-1 day-1 until day 19 of gestation. A caesarean examination was performed on day 29 of gestation. The results obtained were compared with historical control data from 150 mated rabbits. 4. Anaesthesia and catheter implantation caused a slight transient reduction in maternal food consumption and weight gain. Pregnancy rate, pre-implantation loss and early resorption incidence were not affected. 5. Late resorption incidence and post-implantation loss were higher in the infused group by comparison with the historical controls but the individual data did not suggest an effect of treatment. Foetal weight was not adversely influenced. Three of the infused dams each contained one malformed foetus: a possible influence of infusion in the aetiology of these abnormalities cannot be excluded nor confirmed within the limitations of this experiment.