While there's yet to be found literature proving that x-rays are a concern in late gestation in dogs, this definitively remains something to ponder about before proceeding. (pethelpful.com)
The obligate intracellular bacterial pathogen Chlamydophila abortus strain S26 / 3 (formerly the abortion subtype of Chlamydia psittaci) is an important cause of late gestation abortions in ruminants and pigs. (sanger.ac.uk)
By late gestation, only their tails undulate this way. (sciencemag.org)