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Question on Conception dates

I had sex with my Ex-Girlfriend on 05/29/2013 without a condom, I am 100% sure that I did not ejaculate inside of her. On 07/19/2013, my ex-girlfriend had her first ultrasound at 8wd1 and gave me the devastating news that she had sex multiple times with another guy. On 08/08/2013, my ex-girlfriend had a second ultrasound which reflected a 11w0d. My ex-girlfriend says, I'm the father but the dates given on the sonogram does not match my conception date calculator online. I know it's an estimate and I know its cutting it close but I'm very suspicious because she showed up to my house to have sex and wanted me to do it without a condom and ask me to ejaculate inside. Now, I have never ejaculated inside a woman even with a condom and she was mad that I failed to do so that night. So like I said I'm very suspicious. There are two many variables and I'm going through a hard time. Can anyone help?  
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134578 tn?1614729226
Well, this will be something that you won't know a final answer about until the DNA test, so try to stop stressing so hard if possible, this will be a marathon and not a sprint so conserve your emotional energy.  I know, easier said than done.  Until you get the test, all you can to is see if the dates suggest anything.

Regarding gestational age:  if a doctor tells a woman she is X weeks x days pregnant based on an ultrasound, he is saying she is that many weeks from day 1 of her last period.  This is called "gestational age" or GA.  It does NOT mean the doctor is saying the woman conceived on the first day of her last period, but the medical profession starts the pregnancy count on the first day of bleeding because that is a big, obvious signal, and then they calibrate everything to that, ultrasounds and medical textbooks included.  GA length from day 1 of bleeding to full term is 280 days.  (From conception to full term, it is considered to be 266 days. This is because most women ovulate a couple of weeks after the first day of their period.)  

When someone has an ultrasound that says she is '8 weeks 1 day' on July 19, to be able to work with a conception calculator and see if that means you, you first need to count back to get to the first day of the last period (in this case, 8 weeks 1 day from July 19, or 11w0d from August 8.)  The date I get for the first day of lmp is May 23 (please check my work).

Here is what the conception calculator I use says for a first day of last menstrual period of May 23.

     Assumed first day of last menstrual period:  May 23
     Probable date of ovulation:  June 6
     Possible dates of conception:  June 2 to 10
     Due date:  February 27, 2014 (40 weeks)

When your girlfriend came up with those ultrasound results saying her gestational age, did she ever mention a due date to you?  If so, did she say it was February 27?

Anyway, if you had sex on May 29, by the ranges on the calculator and the numbers from her ultrasounds (and the fact that her first one was early), it is not impossible that you are the dad.  The range on the conception calculator says its earliest projected day would be June 2, and sperm can live that long in a woman's reproductive tract.  That said:

-  The ultrasound envisualized the actual baby and measured it.  The dates are not merely based on someone's report of the first day of her last period (which can be problematic even if true, because women can ovulate unusually early or late compared to an "average" cycle, and that would make the moment of conception a different time than "average").  An ultrasound, if it is early, means a better chance that the probable date of ovulation is the one named on the calculator.  

-  You didn't ejaculate (though of course, there can be sperm in the urethra under certain circumstances prior to a sexual event and the sperm can be brought down the urethra by pre-ejaculatory fluid.  This is therefore not a foolproof way to avoid pregnancy.)

-  She had been having sex with someone else.

Regarding the part where you imply that she showed up and wanted to have unprotected sex perhaps because she knew she was already pregnant and was covering the situation:  by the ultrasound dates, this is not true.  She would not have known yet that she was pregnant.  Maybe she could have been having sex with you to cover the fact that she had unprotected sex with someone else that she knew *might* make her pregnant, but even then, it was early for her to ovulate, so it does not seem like that was what she was doing.  Another possibility is that she just dang well wanted a baby, so she was coming over because she wanted to lay down some sperm for the upcoming ovulation.  Oddly, I've also heard that ovulation can make women horny.  So you might give her a bye on the most sinister of your suspicions.  

Had you broken up yet on May 29?  Had she ever said she thought you would be a good dad?  Are you more wealthy or stable than the other guy, i.e., a good catch?  (I once asked this of a guy in Ireland in your situation and he said, "My mother thinks so."  It was pretty funny.)

Anyway, sperm can live in a woman's reproductive tract for 5-6 days.  Some research says longer, but other research counters that it is not looking too tremendously frisky by even day 5, so it might not have the oomph to penetrate an egg.

And although she got her ultrasounds nice and early, there is always a bit of a "plus or minus x days" thing going on with ultrasound counts, though not so much in the eighth week.  Later ultrasounds can be way off for dating purposes, but early ones can be spot on.  If her July ultrasound gave her 8w1d, it is probably reliable within a day or so.  

Here is what I suggest.  Don't fight with her, don't act hostile or rude.  (You will know what is true in the end, there is no point in destroying all vestiges of civility between you this early.)  Ask sometime if she was ever given a due date.  (I hope she gives you one from the first ultrasound, it will be the most useful.)  There is no rule that says you cannot use information gained by being civil, to run things by a conception calculator and see if they give any more clarity. I do think you had better act nicely:  a) just in case you do turn out to be the dad, and b) because it is much easier all the way around and into the future.  Take a joint problem-solving tone.  Say, "Of course, I'll be glad to take a DNA test.  Naturally given that you were not being exclusive with me around that time, you will understand if I am not entirely ready to take your word on this."  This does not mean that you have to go to doctor appointments, go baby-item shopping, or start talking about paying child support.  Tell her, cheerfully and offhandedly as you can manage, "Oh, let's leave that for after the DNA test, ex-honey."  

By the way, since child support is no doubt part of the issue and you do not entirely trust your ex's truth-telling skills, consider getting your DNA test at a lab certified by the courts for determining paternity.  They are reliable and nobody can tamper with the swabs on the way to the mailbox.  If the DNA test ultimately shows you not to be the dad, I assume you will be pleased, but try to cough up a little sympathy also.  Sometimes, and this is true of men as well as women, people want something to be true so much that they overlook some important fact or just convince themselves.  It certainly sounds like she wants you to be the dad.  Don't get everything so tied into knots with fighting now, that she can't admit to you that she made mistake, then.

Anyway, a close thing.  Time will tell, try not to freak out.  I don't think it sounds absolutely like the dad is you, but with tolerances of less than a week all the way around, a test is the only way to get closure.
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Avatar universal
Wow! You've said everything and I mean everything my friends and family said to me.

When I indicated that lot of variables were involved is due to the fact that on the 07/19/2013, I overheard my ex-girlfriend tell the ob/gyn's assistant that her LMP was at 05/13/2013 (this information was provided before U/S was executed). The ob/gyn's assistant gave her a due date of 02/17/2013 (also information provided before U/S was executed). All this information was given without me being in the same room. When I plug in the information, it does not match with the u/s GA or my conception date. However, my conception date is cutting it very close.

I was with her for more than 6 years but in a mutual agreement we broke up the beginning of this year and never had sex until the 05/29. My ex-girlfriend always wanted a baby from me. When I mean by always is she was obsessed with the idea of having a baby and start a family. When her parents heard that she was pregnant they were joyful with the news but at the same time they were a little dissapointed that we weren't married. According to her parents, they were excited because they were going to have their first grandbaby. Also, that even though we weren't married, they knew I was going to take care of my responsibilty.

Now, my relationship with my ex-girlfriend is a bit rocky. Due to the fact that, when I heard the news that she slept with another guy she ask me not to tell her parents. I explained to her that they needed to know because one day I was going to request a paternity test and I didn't want anybody to think that I was that guy that wants to make any excuse not to step up as a father. Her parents know that I'm responsible and that I will take care of what's mine. So, I had a serious conversation with her parents and in a very civil way I told them that their daughter had doubts. Her parents could not believe it and had numerous breakdowns. My ex-girlfriend was so pissed that she cursed me out for telling them. Her parents understood my frustration and could not believe that her daughter put everybody through this situation.

That's the reason why I stopped getting straight answer from her. I can't even get a ob/gyn's due date (if it changed). Here's another variable, that rattles me, at first she said I was the only one, then she admitted having sex with another guy once early March and used a condom. Then, she decides to admit to doing it once again late at the end of June also with a condom. I was so in disbelief that she then confessed using a condom and a plan b pill on both ocassions. Now, I know her and I'm not dumb, when a person finds someone exciting and new they have sex regularly not once every 3 to 4 months. Also, plan b? why? you had a condom! Furthermore, I don't understand why she haven't said anything to the other guy and I'm the only person going through this alone. I had everybody near me say calm down is not yours but it's hard for me to wait 4 to 5 more months without a straight answer. If it is mine, I will be missing a lot from my first unborn child and that kills me.  

In regards to sperm living in my uterus, I remember ejaculating that morning twice from masturbation and urinating that day. Before having sex I took a shower. I know this doesn't help much but I'm being extremely transparent here.  

On another note, Annie I appreciate your kind words and your reply. Thank you and sorry to bother is just that there are several variables that puts me in disbelief. I'm hurt and I don't think my ex-girlfriend understands what I'm going through. If its mine, I will take care of my responsibiliies as a father and move on with my life.  
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Avatar universal
In regards to your question, if I'm wealthier than the other guy, that I don't know but I assume that I am due to her parents not telling me who he is and the fact that they don't want to tell him that her daughter is pregnant. When I asked my ex-girlfriend if the guy was married or had children she did not want to answer and simply nod her head as a I don't know.

Another variable that I forgot to mention was that through the 6 year relationship she always had her period around the 22,23,24,25,26,27,28,29,30 (end of the month and at the latest ending early the next month if LMP was late the previous month) with that being said to me there were regular but I don't recall she ever having a late period like the 13 of the month. I'm so sorry I sound like I'm sherlock holmes but all of these variables were to clear and none of the calculations, friends, family, or even professionals in the field can match all the information that I have (LMP, conception dates, due dates, etc.) So, this is the reason why I'm reaching out.    
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134578 tn?1614729226
You can't rule out her ovulating on the 29th and you can't rule out her having sperm in her system from you or the other guy or both, when she ovulated.  So, the only thing to do is get a DNA test.

If your main problem with all of this (besides being impatient to know) is that you somehow want a prenatal relationship with the baby if it is yours, you can do one of two things.  

-  You can get involved with the doctor appointments, telling your girlfriend that you still will do the DNA test when the baby is born but feel obliged to come to the appointments in case the baby ultimately proves to be yours.  It isn't going to cost you any money to go, and you might learn something.  

-  If you don't mind spending two thousand dollars or so, get a prenatal DNA test.  You have to be careful about the lab -- some of those that advertise on the Internet are not trustworthy.  But if you feel you must know for sure before the baby is born and have the money to spend to do it, that is the way to go.  Here is an article on one of the best of the companies.  They work with labs all over the country, who take the blood samples.


In the meantime, please stop telling the story around.  Her parents know and unfortunately your friends know, that is enough.  The parents needed to know but saying any more to anyone else will do even more damage and make things harder.  If your friends ask, just model dignity.  Say you'll be doing a DNA test when the time comes, and leave it at that.  Don't act all interestingly freaked out, it will just make the gossip more fun and salacious for them.  After the child comes, there would always be an asterisk in their stories to each other -- "Here comes Pat with his kid, if it is his kid -- nyuk, nyuk, nyuk" or "There is Sally, and that kid she said was Pat's but he was from some guy, nyuk, nyuk, nyuk."  Don't do this to the kid, no matter how mad you are at your ex.  No child deserves to be a living memorial to a salacious story about his origins every time your buddies see him around.

I might also add that you could try to work on your sense of grievance that she had sex with this other guy.  You two were broken up in May.

If I had to guess, I would say that one interpretation that fits how she has behaved is that she had sex with the other guy in late May and then had sex with you, all within a very short time.  She is pregnant and something about the sex with Mr. Wrong has convinced her it could not be him (like, she took Plan B after him and thinks that solved the problem, or he wore protection, or he pulled out) or else she has simply convinced herself it is not him because of the horrible mess it would be if it were.  She thinks she is doing what is in the best interest of the child, in focusing on you as dad.
I am not saying that you should accept any of this, but if this is why she is doing what she is doing, unacceptable as it is, it is at least understandable.

That's all guesswork, though.  It is a shame she was not more forthright about the details so you could understand why she is so adamant the dad is you despite the presence in her life of someone else.  But by now she is not going to want to tell you much.  (I'd be kind of surprised if she wants you at the medical appointments, but maybe she will.)  

Do your best in the situation, and try to calm down.  Time will answer this if nothing else does.
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