Pregnancy Due Date Discrepancy: Seeking Second Opinion

Question
I am 28 yrs old and have a 9 yr old son. I had a positive pregnancy test on March 10th. I had a period on Jan. 6th and a really light one on Feb. 12th. I kindof had the feeling in Jan. that I may be pregnant but proceeded to wait until my next months period to do anything. I went to the dr on March 21st and had a 3d ultrasound done and he thought that I was possibly 3.5 to 5 wks pregnant, but possibly 8 and the fetus stopped growing at 3, but told me to return in 2 wks for another ultrasound. I had to return only a wk later due to severe cramping, at this ultrasound visit he informed me that I was 8-12 wks along. My dr is now telling me that I am 14 wks along w/ a due date of Nov. 16th. I went to the dr just this wk due to not feeling the baby move, which I have been feeling for 2 wks now and the dr basically told me I didn't know what I was talking about but I had them check for heartbeat(which was really slow) just to reassure myself. None of the numbers add up due to the fact that I didn't have any sexual contact nor was I anywhere near a man during the estimated time of conception. How do I go about getting the right information on a due date? Am I better off switching drs just to be safe?

Answer
Dear Jessie

Let me clarify the following facts to you:

1- Trust is a basic component between you and your doctor. If you do not feel comfortable with him/her, seek a second opinion or switch to another doctor.

2- Variations in estimating the true gestational age by ultrasound between 4 to 9 weeks are really wide and therefore are not accurate enough except to confirm a gestational age calculated by a mother who is sure about the dates of her lmp

3- If you are not sure about the dates of your lmp, a serial ultrasound scanning would be the best to date your pregnancy's age provided that at least 2 ultrasounds are taken in the first 12 weeks of pregnancy. This should be followed by at least, a 3rd in the second trimester (after 12 weeks) before giving accurate fetal age.

I hope these info are helpful.

Good Luck