Pregnancy Conception Date Calculator: Calculate Your Due Date

Question
Hi Brenda!
I found out that I was pregnant on May 27th. My LMP was approx April 24th and lasted until the 29th.(I can't remember if it was the 24th or 25th)I should also note that I have 30-31 day periods. I had sex on May 1st and May 2nd and then on the 15th(at night time). I have checked conception calenders and it doesn't seem that I had sex during my "typical" ovulation time. What day would I have gotten preganant on? I appreciate your time in answering my question. Thank you.

Answer
Dear Lisa,

Well, you are right. I calculate and approximate conception date of anywhere from 5/9-11. So, I would suspect that you probably started the 25th (since you can't remember) and maybe ovulated slightly late in the cycle. The most likely sexual encounter to have resulted in conception of the three you have shared would be the encounter on the 15th.

Here's the thing - your OB will likely be doing an ultrasound before the 12th week of pregnancy. That ultrasound will date the pregnancy and will be the most accurate tool in doing so - even more accurate than using LMP. But remember (because it is extremely confusing) when the ultrasound gives you a date - that is based on LMP. ALL pregnancy dating is. So, that would mean that you would deduct approximately two weeks and that will give you and estimated conception date. So...for example, we'll ASSUME you did conceive on 5/15. Let's say you have an ultrasound on 7/1. That ultrasound would give you an approximate gestational age of 8 weeks, 5 days. (That date is conception date plus two weeks - an automatic calculation which is made based on the normal length of menstrual cycles.)

I hope that makes sense and helps you. Be assured - the dating of that first ultrasound will be MOST accurate. I wish you well.

Brenda