JC, my adult female garter, turned out to have been pregnant when I got her. I got her at the end of May, beginning of June a year ago. She didn't eat anything at all from the day I got her until August 3, after having 20 babies on August 2! She only shed once before the litter was born, that shed was about a week after I first got her, not close to the time of the birth at all!