How do I tell if Lexie is pregnant? I didn't know she was in her heat until one day she got on my bed and spotted on it. SHe was around Romeo all of the time before that. Actually I know they mated because that happened before I noticed the bleeding. After I saw the spots on my bed I checked her out and she was swollen. (Her first heat was light so she kept herself clean and had little swelling. He is 8 months...I was not sure that was old enough to breed. Anyway now...2 weeks later she is swelling on her tummy. I don't know when this heat cycle started but the spotting ended about a week after they got together and the swelling on her tummy and nipples has increased. My vet advises me to treat it like a pregnancy just incase but told me I would not know until later. I thought I would ask you guys on here because many of you have bred yorkies. Any help is appreciated!!!