Understanding Early Pregnancy: 6-Week Ultrasound and Dating Accuracy

Question
The first time I went to the doctor I was told I was 6 weeks pregnant.  Which I was told meant that I conceived around the end of March.  My due date at the 6 week ultrasound was said to be January 28th.  I know this sounds crazy but it is possible that I could have conceived this baby in January?   ( I just need a little relief)I am sure it is not possible but like I said I need some security.  Basically what I want to know is how accurate is that first ultrasound?  thanks

Answer
Hi Sara,

The dates are not adding up based on what you gave me.  If your 6 week ultrasound gave you a due date of January 28th, based on my pregnancy wheel calculator you would have conceived around MAY 8th.  If your due date is in January, there is no way that you could have conceived in January the previous year.  I'm confused about your dates, but in any case the 6 week ultrasound you had is accurate in dating by +/- three to five days.