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Accuracy of early ultrasounds/not sure of who the dad might be.

This is going to be super long .Im a regular 31 day cycle girl. I know about sperm living 3-7 days. I know about needing paternity testing i know condoms arent 100% effective.   I had sex with 2 different guys 3-4 days apart. First one was with a condom second one was without a condom( had sex with second guy 2 days in a row). Thing is before i went for a dating scan i tryed to work out my own due date based on my cycles and the time the majority of women that ovulate on a 31 day cycle and put my ovulation dates on the day i had sex with 1st and the 2nd guy. Well 2 days after the last encounter i Got strong ovulation pains for about 5 min(i get every month after i had DD just didnt track my cycle just knew i had my period every 29th of every month) so it came down to my due dates being the day i had sex with 2nd Guy( Due date- july 10) and the day i was feeling ovulation pains (due date july 12th) at my dating scan i was told i was 6weeks and 4 days (due july 13th)!! That asuming i ovulated day after when i had strong ov pains being cycle day 22 wich is 2 late for ovulation my cycles never been irregular so that would put me on a 9 day luteal phase(asuming)  so really i just want to know how accurate is an ultrasound at 6 weeks and 4 days i know it can be off (+5/-5) but how likely is that to happen? And if ultrasound was right on is it really possible to have a successful pregnancy with short luteal phase???  and if it was off i know ov would most likely be the day that i had sex with 2nd guy but if thats so then its to close to the 1st guy aswell then i guess id never know if 1st guy is the dad or second guy. Kind of wishing ultrasound was right on. Judge awaaay
2 Responses
134578 tn?1517087675
You say your periods come every 31 days and put a lot of faith in your computations based on this, but then say you always have a period on the 29th of every month. Both things can't be true -- April, June and November have only 30 days in them and February has 28 or 29; if your periods always come on the 29th that would mean you are irregular, not regular. And remarkable, too, since it would mean your periods can read a calendar and tell if it is April and not May, and vary the cycle length to always hit the 29th of the month. So, the first piece of feedback is don't be so sure your period arrived on the 29th, especially if you haven't been keeping track. You are using this to think what must be wrong is a medical test (ultrasound) instead of your assessment of when you must have ovulated based on a cycle month that merely assumes your period began on the 29th. It is possible that your periods have shifted slightly in relation to the calendar, if you haven't been charting them.

Can you give dates, not just analysis? When did you have the sex with each guy, when did you have the strong pain, when did you have the ultrasound? The only date you mentioned is your estimated due date, all the rest is interpretation or only relative to the other incidents in the story. Your interpretation might be perfect, but there is no way to answer your question without the data.  .
Hmm my period recently started being 29th of every month for 4 months before falling pregnant tbh. Before they were on day 28th. I could be wrong about my cycles then but don't think it would vary from much 30-31 My last period was sep 29th Had sex with first guy october 14th cycle day 16. Then had sex with second guy october 16,17th being cycle day 18,19. On october 19 i had ov pains at night . due dates from oct 17th( july 10) due date from the ov pains (july 12) i had my first ultrasound on november 21. My calendar i put i was 6 weeks and 5 days or 7 weeks. When i went for dating scan they put me at 6 weeks 4 days.
If they told you on November 21 from looking at the embryo via ultrasound that you were due on July 13, that would be an October 20 estimated date of conception (with a +/-  1 or maybe 2 day margin for error either direction at 6w4d GA). Except you are questioning it because you assume your cycles are like clockwork and your periods always come at 30 to 31 days, including that your period was intending to come on October 29, which might push conception back to the 15th.

Women's cycles will vary. (They even shift to match other women, a phenomenon new female college roommates often experience. Any new women in your workplace?) Ultrasound readings are medical tests and the people doing them are usually highly trained, they are not known to be randomly wrong.

In your shoes, I would not use the idea that your cycles always come on the dot at 30-31 days to disregard what an ultrasound says. The ultrasound findings also back up the fact that you had what you describe as ovulation pains on the 19th.

(If you did get pregnant on or around the 20th, that does not mean a 9-day luteal cycle, see the above about "women's cycles vary.")

Unfortunately, the sex with both guys being on October 14 and October 16 puts them both in the range of possibility, if conception was around October 20 as the ultrasound says it was. The second guy has a slightly stronger chance than the first guy, but using an ultrasound measurement at 6w4d to try to determine a conception date, you have to give it a +/- 1-2 day margin for error, which means the guy from the 14th is still in there. At the least, he needs to be in on the DNA testing.

If you have a boatload of spare money, see if the guys will test with you before the baby is born, using a top quality lab for doing prenatal DNA tests. Test with both guys not just one, so you can tell from one guy's positive test that the other guy's negative test is correct. I'd use Ravgen or the DDC. Don't test with just one guy -- if you get a negative, you'll worry that the test was wrong.

If that would be just a big fat waste of all that money, test after the baby comes. It costs a tenth as much to do a post-natal DNA test compared to the reliable prenatal tests. Call the family courts in your area of jurisdiction and ask the judge's clerk for a list of labs approved by the court for legally determining paternity. Make sure both guys go; if possible go with them so you can see they haven't sent a ringer in their place, and if you can't get one of them to go, the law is on your side, see your lawyer. You do need to test after the baby comes to make this determination legally, and you need to know for sure anyway, it is the only correct thing to do for all four of your sakes.

Sorry you are in this spot. Congratulations on your upcoming child. Many women would trade places with you right now, even not knowing what you don't know.

Take care.
Very helpful information. I have one more question. Does the time of sex reduce chances by any ?.i Had sex with condom guy at 1am on Oct 14th.
Sperm don't care if it is 1 am.
134578 tn?1517087675
One other way to interpret the data is that on the 14th you ovulated and on the 19th the pain you felt was implantation. Not that this ties in with the medical evidence from the ultrasound, however. I'm just mentioning it to back up the fact that you do need to do the DNA test with both guys.
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