My sister was telling me about a lady at her work whom had a baby last year, then a few months later started her periods....she was quite a large lady...anyway she carried on with life, then in February found out she was 7 months pregnant !!!!!! She is due in April !!!!! SHe didnt even know. SHe has a 2 year old, 1 year old and will have a newborn soon.....she had her periods so didnt suspect anything....amazing...