Pregnancy Conception Date: Determining the Father - Expert Explanation

Question
The date of my last period was Sept 27th, i had sex with my ex husband on Oct 3rd, then had sex again on October 11th. I'm not sure who the father is. The doctor said i'm 9 6/7 weeks which i'm not sure what that means, but they said my conception date is the 11th of october. So would this mean it could be my ex husband, or the other guy i slept with on the 11th? I'm not sure how conception goes, i know they base the pregnancy off the first day of my last period, but i also thought that you dont automatically conceive the minute you have sex, i thought it could take 1-2 weeks. So would that make it my ex husbands?

Answer
Hi Shannon :)

Thankyou for writing!

Let me explain how to you, how this all works. As a rule, a lady will ovulate 14 days from day 1 of their period. Now again, for some ladies, it may be earlier, or later, but that generally when it happens.

Conception doesnt take 1-2 weeks after intercourse. Infact, it can happen the same night you had sex, or a couple of days later. You see, sperm can live in your body between 3-4 days. So if you have sex, its possible you might not actually become pregnant till 1-2 days after intercourse. But sperm dies at about 3 days after ejaculation, making it impossible for conception to occur any later.

Now, I did some calcuations of my own, according to the dates you gave me. Again, this is all with assumption that you have a normal 28 day cycle.

My dates, are exactly the same as your doctors. You are exactly as of today, 9 weeks, and 6 days pregnant. You ovulated, October 11th, and your estimated due date to have this baby is July the 4th, of 2007.

So, this conclusively rules out your exhusband. The other person you had intercourse with, on October 11th is indeed the father of your baby.

The only way to confirm these dates,conclusively is to have an ultrasound done to confirm gestational age of the fetus.

So yes, you can completely rule out your exhusband as being the father of this child.

If you have anymore concerns, or questions please dont hesitate to write back :)

Thanks for writing

-Kristy