2 potential fathers, help.

[Taylortails]

I had UPSI with my ex on my heavy period, 4 days into my cycle starting 25th of December. (So sex was the 29th @ 2am). I was single and he did not ejaculate in me, however I know that the "pull out method" is not a form of contraception.

I then had UPSI with my current partner on the 1st, 2nd and 4th of January. I am 30 weeks and 2 days pregnant today. (My current partner and I were broken up for a long period of time before we slept together again, due to different lifestyles and we got back together before we knew I was pregnant) I will also say, he is aware of my encounter with my ex.

I had an early pregnancy scan due to bleeding on the 20th of Feb, which told me I was 8 weeks and so many days, but the Sonographer told me it would mean my most probable date of conception was the 6th of January as my due date was the 29th Sept, which would be 9 days after my encounter with my ex and she said it's very unlikely to be my ex's. She also said that the early pregnancy scans are more accurate in Fetal age as foetuses tend to grow at a similar rate before 10-12 weeks.

However, at my 12 weeks scan, she said I was due 27th of September and told me my probable date of conception was the 4th of January.

I am aware most sperm lives 3-5 days and in some circumstances can live 7 days in great conditions, however I have looked at scientific medical studies where doctors have studied conception in comparison to days before ovulation of sex which could of helped conceive a child and the probabilities and percentages are low (I know there are still possibilities and this is information I have recently found out)

My main questions are:

How accurate are early pregnancy scans or even normal scans in determining the conception date?

And

Which dates could I have ovulated for the time I am pregnant now? (Due September 27th/29th)

I know a paternity test is the only 100% guarantee but I would like to weigh out probabilities.

No judgement please, I'm terrified and very alone.

[Taylortails]

This is the chart of intercourse and ovulation. pregnant-naturally.com/get-...

[CocoB]

your weeks are usually measured from the first day of your period, and women usually ovulate 12 days after their period. I have found that the scans are accurate give or take a day or 2.

You say you had sex during your heavy period, so more than likely you weren’t ovulating then, even though it is possible to conceive during bleeding, but I’d say your probably conceived with your current partner.

[Narao]

Oh darling this so so confusing I can feel you , relax and ease your mind , you are pregnant and you need to calm down for the baby and for your health , all I can say is that you are not alone and my guess you are pregnant from ur partner because first of all you were on ur period when u had sex with ur ex , and the probabilities of getting pregnant while on your period are low , but since there is a small chance we get to the second of all , he did NOT ejaculate inside of u so the chances are almost none !! U had sex with your partner when u were ovulating , do not listen to the pregnancy scan because there is no way to be accurate at early pregnancy .