Please help. I'm 10 weeks pregnant and never had chicken pox but was vaccinated once, they tested me and my

blood showed that I tested positive for both antibodies. My doctor and midwife are completely baffled and they are sending me to maternal fetal medicine in a big hospital in town. They called Maternal fetal medicina and they are completely baffled as well. Never had symptoms except my chest was the itchiest its ever been. No blisters, no bumps, just itchy for about 3 days after going to the beach. Does anyone know what could have caused this and what it means? Whenever I try and look it up, alls I can read is birth defects, birth defects, birth defects.