You had an ultrasound on February 12, and she gave you an EDD that was 3 days later than you thought it should be, and this makes you afraid that you didn't get pregnant on the 11th but instead on the 14th? How far along (in weeks) did the second place say you are? And you said that your ex was probably not the dad (from the sex on the 15th) because you used a condom that time? (But that you didn't use a condom on the 18th.)
I think your margins are so slim that you are definitely going to have to have a DNA test, but that especially if the baby is a girl it sounds like your boyfriend's baby and not your ex's. Unfortunately, by your 8th week of pregnancy (counted from the first day of your last period) there does begin to be a slight margin for error when using ultrasounds to determine the conception date, though it is not as huge of a margin as it is by your 12th week. That's why I was asking how many weeks along they told you that you were at the second place.
Incidentally, you say "I didn't have sex on any of the days [the calculators] tell me I should have had sex to get pregnant." You don't need to, since sperm lives up to 5 days in your system (some research says longer). The sex on the 10th would have provided you with sperm that could well have been still alive in your system when you had sex on the 15th.
My ultrasound on 2/3 determined I was 5wks and 2 days. So that gave me the 10/4/15 DD.
My scan on 2/12 has three sets of numbers. One reading 6 wks 4 days (which I'm assuming is the baby's measurements) and that would actually match the growth from the initial scan on 2/3. But then under it it has the "sac" measurement which reads 5wks 6days. And at the very bottom it has "ultrasound acuson MA" 6wks 1 day EDD 10/7/15. So that's why I'm confused. The sonographer didn't speak at all and didn't give me any info about the measurements or even the heart beat.
So, are you saying if the baby is a girl, the baby would be my current boyfriend's?
I think I just understood by rereading your comment and what you meant if the baby was a girl. If the baby is a girl, then I'd most likely have to get the DNA test done, correct? And if it's a boy, then the baby would actually be my current boyfriend's child, is that right?
Looking over my ultrasound photos from my second scan on 2/12, (I got 13 images total) three have CRL measurements: one is 6.6mm 6w4d, the second is 6.3 mm 6w4d, and the third is 7.4mm 6w5d.
And then three other photos have the SAC measurements: 1) 18.3mm 6w1d, 2) 11.5mm 5w2d, 3) 15.2mm 5w6d.
The scan with what just looks like a final measurement numbers plugged in (no baby in that one) is where I got the CRL 6.8mm 6w4d SAC 15.0 5w6d "ultrasound acuson MA" 6wks 1 day EDD 10/7/15.
So I'm not sure if this actually is correct with the growth timing from my first scan on 2/3...and they just estimated based off the slightly different measurements to get the 10/7/15 EDD instead of the first one my doctor gave me which was 10/04/15? Btw, both ultrasounds were done vaginally.
I hope this isn't too confusing and is enough info to get some clarification to be able to get an exact conception time frame. I just want my current boyfriend to be the father, not my ex. And as I said, I used a condom with the ex on 1/15.
The boy and girl thing is only useful in certain circumstances. If a woman were to have had sex on January 1 and no other time in January, and she KNEW (because a doctor was looking at your ovaries with a microscope and saw it happen) that she ovulated on January 6, the likelihood is very strong that the baby would be a girl. This is because sperm carrying the y chromosome apparently swim faster and die sooner, and sperm carrying the x chromosome swim more slowly and live longer. According to this theory (look up the "Shettles method") the woman would not have had any live male-carrying sperm left in her body by January 6, but would still have had some female-carrying sperm alive there. I just commented that if you had sex on the 10th with your boyfriend, and IF (a very big if) you ovulated a few days later than the 10th but still too early for Mr. 15th, your boyfriend's girl sperms would have been around to do the fertilizing. But none of this is proof of anything, and none would be strong enough evidence to not need a DNA test. This is because for one thing, you don't know how close to the sex on the 10th you actually ovulated (girl and boy sperm could be in your system together for a while) and x- and y-carrying sperm have not read the Shettles book so they can die or maintain in the approved fashion. In other words, I don't know how strong the actual science is behind that method. If you do a gender scan at 18 weeks and the baby is a girl, and if your due date remains at 10/4, then you might be able to use this to hope that everything is as it should be. But you would still need a DNA test.
In your shoes, I would take all the scans and reports and have a sit-down with your doctor and explain the situation and go over everything thoroughly. The doc can explain why one says the 4th and one says the 7th (it is possible that the ultrasound in your fifth week was a tiny bit too early for certainty, though it should suffice). But, all in all, you still will need to test, there is really no way around it. I think that condoms usually do what they are intended to do, but I think in this kind of situation the only fair thing to do is a DNA test, in the end.
*her ovaries, not your ovaries