When did I truly conceive, and is a paternity test needed?

[Guest5354]

I had unprotected sex on January 20/21 during my ovulation time with guy number 1.  I ended up taking plan B on the 21st. On January 24 I had protected sex with a different man and he did not end up finishing. Since I took plan B, I think my period the following week which started on Feb 2 and ended on the 6 (which was on time) was a little lighter than usual and it seemed a little different than my normal periods are. I believed since I got a period I was fine but now I’m wondering if I by chance conceived during this period and this is why.. I continued to have unprotected sex with the first man all throughout February Many of those times during my ovulation times, and I ended up missing my period come the beginning of March and did not have sex with anyone else during February or March. When I went to my first ultrasound they told me I was due on November 12.  After going to my second ultrasound appointment on June 23 when I was supposedly 20 weeks along, my due date ended up getting changed to November 8 due to how the baby was measuring. I’ve looked into conception calculations to see when I actually conceived and a few of them are contradicting each other. One is saying I could’ve conceived on January 28/ 29 whereas others are saying I would have conceived during the week of February 9 which puts me a week after my strange period. Since these conception dates are very different I’m lost as to whether or not a paternity test is going to be needed and or when I truly conceived. Does anyone have any advice on what I should do? Or if a test is even needed?

[ppowb]

I don’t see any way to avoid the idea that you got pregnant at an ovulation close to Feb 19th. PlanB can postpone the date of the next period and ovulation but does not seem to have done so in this case.

[AnnieBrooke]

Hi, I don't think a test is needed, since it doesn't sound like the sex January 24 had anything to do with anything. It's hard to believe you found a conception calculator that said January 28/29 for a due date of November 8 or 12 unless you plugged in the information in the wrong slots. But let's check your work.

You said "When I went to my first ultrasound they told me I was due on November 12." How early was that first ultrasound? (You said your second ultrasound was in your 20th week, but not when your first ultrasound was. ) If it was early, like in your 7th week, I would tend to believe the due date it gave you more than one in your 20th week, since babies can grow at different rates and trying to determine conception from an ultrasound measurement later in the pregnancy is less accurate than earlier in the pregnancy.

But in any case, why would even November 8 make you think you got pregnant on January 24? Have you ever worked out what your due date would have been if you got pregnant from the sex on January 24? (October 16, right?) November 8 is more than three weeks later than that, and November 12 is almost 4 weeks later.

When you say you're worried and "this is why," I hope you don't mean you're worried because in your 20th week they changed your due date by a mere 4 days. They would had to have changed your due date by more like 4 weeks to give the guy on the 24th a chance.