Thanks for your query. If you are not sure when you got impregnated, kindly correlate with ultrasound
, best is when it is done between 9-11 weeks i.e DATING SCAN. Or else 2 scans done in 2nd trimester should correlate with eachother.
I hope this information has been both informative and helpful for you. In case of any doubt, I will be available for follow ups.
Wish you good health.