Ultrasound-guided collection of amniotic fluid in pregnant rats

Here we present an echographic method to withdraw amniotic fluid from pregnant rats. The method could be an alternative to the surgical amniotic fluid collection methods used currently. On day 18 of gestation, pregnant Sprague-Dawley rats underwent amniotic sac puncture by either surgical procedure or echographically guided method. This study evaluated the effect of the 2 collection procedures on parturition day, number of pups per litter, and weight of newborns compared with those of a control group without any fluid collection. These parameters did not differ statistically across groups. However, the echographically guided method did not require surgery or postsurgical recovery and was therefore advantageous from the perspective of animal use. Moreover ultrasound-guided collection allows experimental designs that require collection of multiple samples from the same animal during a single pregnancy.