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DNA Paternity question: Am I overthinking?

My last cycle was December 20th-24th. I had sex on the 25th the day after my period ended, early morning  (light spotting) and then again on New Years (early morning). I have a normal cycle 28-30 days and my period is always 5 days long. I am due September 25th. My ultrasounds are spot on with NY intercourse. My first ultrasound they said I had just hit 5 weeks because it was literally nothing to see except a gestational sac. If I would have conceived a few days after Christmas wouldn’t that ultrasound been further along into the 6th week? I did ask my doctor and she said I likely conceived 31st-January 5th. Am I overthinking this?
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Avatar universal
Hi! Just an update. It was the second mans baby as I suspected. I went through accurate DNA. 99.9% it is his. Which aligns with my ovulation and ultrasound.
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That's great news! Glad you got a firm answer.
134578 tn?1693250592
COMMUNITY LEADER
Hi, what was the date of your first ultrasound? (The calendar date, not the "5 weeks" number.)

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Hi! The date was January 25th.
My second ultrasound was February 13th 7 weeks 6 days
And, at which ultrasound did they tell you that you were due September 25?
The 5th week ultrasound did not give me a due date because it’s just an ultrasound clinic. I went to my doctor February 7th and she gave me that date without and ultrasound. I went back on the 13th which was my first ultrasound with her and she said the same date.
Hmm. I asked because you're splitting a very fine difference here in terms of the dates. Sperm from the guy on December 25 could have been alive in your body as long as up until the 30th or 31st, and the due date (if your doctor used your ultrasound results to affirm the due date she gave you based on your last period) suggests conception not a comfortable margin later, around January 4.  If the doctor simply stayed with the same due date she originally gave you, which was based on when your last period was, you can't rely on the number to be pinpoint in its accuracy. Did she know you were trying to determine which of two guys was the dad? And did she say at the time of your seventh-week ultrasound that the ultrasound measurements of the embryo confirmed the earlier estimated due date that was based only on your period?
No she did not know it was two different people but I she did say the measurements aligned with the due date. She said unless I have an irregular cycle or shorter cycle then I wouldn’t ovulate early or next fertile then day after my cycle.
Ovulation wouldn't have to be the day after your cycle ended. Sperm can live 4-6 days in your body. So the range to be worried about from guy #1 is from the 25th to the 31st, not just to the 26th.

If your doctor specifically mentioned at the time of your seventh-week ultrasound that the measurements of the embryo as seen in the ultrasound scan "aligned with the due date" you had already been given, you can assume that you ovulated on the 3rd or 4th (eggs that haven't been fertilized last about a day, so ovulation could be the day before conception or the day of conception). If you did ovulate at that time, the sperm from the guy on the 25th would have no longer been viable. You said you had sex with the second guy "on New Year's (early morning)," I assume that's January 1? If everything in the assumptions above about what the doctor said is true, that second guy would have the much more likely chance of being the dad.
But wouldn’t I need to be in my fertile week on the 25th in order for the sperm to stick around? I’m usually never fertile right after my cycle ends
When an app refers to a "fertile week," it's talking about when to have sex or not to have sex, not whether the woman's egg is present. For example, say a woman's app computes that she is due to ovulate on the 12th. The app would tell her that her "fertile week" is from the 6th to the 13th. This isn't because it thinks she might ovulate on the 6th, it's to cover the 4-6 days sperm can live in advance of ovulation and still get the woman pregnant, plus the 24-36 hours of an egg's life.

Sperm can live happily in the woman's reproductive tract any time of the month. The environment there is perfect for its survival: moist and the temperature is right and there is no oxygen to kill it. A woman's cervical mucus is said to be more hospitable a few days before her ovulation, but this doesn't mean non-ovulatory mucus kills all incoming sperm. (Besides, mucus becomes hospitable before ovulation, and a woman can ovulate any time in her cycle.)

On average, women are expected to ovulate about 14-15 days before their next period. However, scientists who have studied women's ovulation say that this average is not what happens to everyone. Charting when women do ovulate, they produce bell-shaped curves, not flat lines with a spike right in the center at day 14 for everyone.

Ovulating on day 6 would be considered early, but ovulating from day 10 forward would not be uncommon. This means the first guy's sperm could have still been viable if you happened to have ovulated around then in your cycle. If you have been taking your temp and charting when you ovulate for several months, this should give you an idea of your specific ovulation history in relation to your next period, and that will help you assess the chance of having ovulated in that slightly early time frame.

Given that your doctor did say that your embryo's measurements and developmental markers "aligned with your due date" (and since she said this at a seventh-week ultrasound), it does sound like the first guy's sperm would have been dead by about 4 days before the ovulation date suggested by the ultrasound. In your shoes I wouldn't be entirely thrilled that the gap is only 4 days, but at least it's more helpful information than if they totally overlapped. It seems fair to go through the pregnancy assuming the second guy is the dad, but to do a DNA test with both guys when the baby comes, just to put the whole question to rest.

If both guys are aware of the situation and want to know now, the three of you could do a prenatal DNA test right away and split the cost three ways. (This is the way it would happen in a truly equitable world, but obviously not every woman is in this situation with the two men.) Testing when the baby comes is about as good, though, since you are obviously keeping the baby no matter what, and it's about a tenth as costly as prenatal testing. Please test with both men, it saves a lot of worry later about whether the test was right. One guy's test comes up positive and the other negative, and they back each other up.

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