Carbon monoxide

Valeria

Hi , I am 27 weeks pregnant, since I was 18 weeks I had a high reading of carbon monoxide , we check where we live , the car and everything is fine , I have a monitor always with me and is 0. I went to a privet clinic to get a blood test , and my results come back today with high reading again. I don’t smoke and my appartment is electric ,car is clean , I don’t understand and I am very worry. Is someone had the same ? Or have an idea of what can I do ?