We had a scan on the 23rd of Oct and baby measured 43.2 mm. We were told 11w 4d. This dates to 17 Aug 2012 for average ovulation with preceding days being fertility days. I was across the country from 6 Aug to 23 Aug. How accurate is the test? Measurement taken several times. Afraid its not mine. Please help me put this out of my mind or confirm. Thank you.