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Gestational Age?
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Gestational Age?

Here is my dilemma:

I found out about 1 1/2 weeks ago that I'm going to be a dad......of twins.  The mother of the babies just found out as well, even though she is around 5 months pregnant.  

She was on the birth control shot and the Dr.'s told her that her period would be very sporadic and absent for up to a year so she wasn't alarmed about missing her menstruation cycle.  She also didn't have any morning sickness to speak of.  Another important point is, she doesn't drink or smoke (thank god).

She is 20 years old and we had a short relationship that ended on good terms.  We are now in a pickle.  

I'll give you the exact details about her Menstruation cycle and the date we were together and hopefully you can let me know if I have reason to be concerned about her honesty.

1.)  We were together on 9/2/07 Sunday and she claims this is the first day of her LMP.  I do know she was on her period that day, 100% positive, although I'm not sure if it was her first day.  

2.) We had unprotected sex on 9/15/07 Saturday.... (Probably right smack dab in the middle of her ovulation cycle...so based on this I'm thinking they are mine).  I did not ejaculate in her.  If I did impregnate her on this night the gestational age of the baby would be about 23 weeks 4 days, 165 days from her LMP.  Based on a 37 week pregnancy (common for twins) the due date would be around mid-May.    

3.) She got an ultrasound on 2/13/08 and everything looked healthy and no problems to speak of.
Here, however, is my dilemma.  The report and analysis of the ultrasound reports that the big twin baby's gestational age is estimated to be around 19 weeks 4 days...and the smaller twin almost 1 week behind that and the probable due date being early July.  That puts them at almost a full cycle behind where they should be.  

In the research I've conducted, I realize that the accuracy of ultrasounds in determining gestational age can be sketchy at best the longer the pregnancy but they are usually only + or - two weeks.....not four weeks as in my case.  

I also realize that growth rates may be different for twin babies as compared to singletons, however, that usually isn't recognized until the third trimester and twins usually grow faster.

She swears that she wasn't with anyone else around this time.  Should she be trusted and should I be concerned about the health of my babies or both.  Oh.....I do plan on getting a paternity test to make sure.

Question #1-  Is it possible for the ultrasound to underestimate my babies gestational age by 4 weeks?

Question #2- If they are my kids and are small for gestational age (maybe due to malnourishment) what can be done now to catch up....if anything.

Question #3- What other concerns should I have?  I'm going into the Dr. with her on Wednesday.



Thank you so much for your time.    

nemt4paul

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27 Comments Post a Comment
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354373_tn?1299188126
WOW...I have to say that I'm very impressed with all of the research that you have done...You must be so concerned/excited, etc.
If the date of her LMP is correct (9/2) and you had unprotected sex on 9/15, then there is certainly a good chance of the babies being yours.....The only SURE way to find out is the paternity test, which you mentioned that you plan on having done.  
If you believe that she did now have sex with anyone other than you around that time, then I would have to say that you are the father.
As far as the twins measuring 4 weeks behind, depending on the quality of the U/S equipment, the estimated dates may be off......I'm not sure of the normal leeway though.....4 weeks sounds like a long time.  I was pregnant with twins in the fall, had an U/S and they were measuring only 7 1/2 weeks (I was at 9 weeks), they saw no heartbeats in either....I asked if maybe they were smaller due to their being twins and they said no......Twins develop at the same rate, they are just generally born earlier than singletons.....
You mentioned malnourishment....Does the Mom have an eating disorder?
I hope I was of some help, although I'm not sure I was....
I want to commend you for your involvment in this situtaion.....You sound like an exceptional person.
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427097_tn?1210954367
thanks for the info Kelly and no she doesn't have an eating disorder.  

She was, however, gaining weight ( due to pregnancy) and not eating well enough, being concerned about her weight gain.  

I want to believe her 100% about not being with anyone else, so I can ease my nerves and just deal with the challenges that lie ahead.

Thanks again.
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354373_tn?1299188126
Most people are good judges of character.....If you truly feel that she's telling the truth, all you can do is be supportive throughout the pregnancy and see what comes of it after you have the paternity test done.....It sounds like you are an intelligent person who can make good decisions.....best of luck and be sure to keep us (on this post) updated in the future, or if you have further questions.
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428345_tn?1204214248
My best friend had twins about three weeks ago. She is certain of the date of conception because it was done through invetro(sp). She had some of the same concerns you do regarding her children. When she was about 25 weeks gestation her doctor did an ultrasound and told her that she was measuring to be only 21 and 2 days for one of the babies and 22 and 1 with the other. It is POSSIBLE for babies to measure smaller and some twins develop at a slower rate than others. Also, from personal expierience, it is quite possible that the ultrasound is wrong on the age and weight of the babies. I was told that my daughter would weigh somewhere around 7 to 7 and 1/2 pounds when she was born and she was 8lbs. 14 oz. Good luck with everything and I hope I was somewhat helpful.
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Avatar_f_tn
Was this the first ultrasound that she has had? I know that the later in the pregnancy the ultrasound is done, the more inaccurate it can be. I don't know 4 weeks seems like alot. The reason I am asking about the earlier ultrasounds is because at 6-8 weeks, there is no way an ultrasound could be that much off, unless the babies are not growing the way they should be.
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427097_tn?1210954367
Ian--Yes this was her first ultrasound.  

Mommy2Tay-Thanks....that's good info.
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427097_tn?1210954367
Thanks for all the comments....I'm going in tomorrow.
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355049_tn?1272259988
Twins can measure behind what they should be. They normally do... I have twins all throughout my family 4sets within the last year in a half... If she ovulated around 13-17th then she should be about 25wks if she got pregnant than. Sperm can live for up to 5 days, so if she ovulated later and the sperm was still thriving than she would be only a week behind. Although twins do measure differently.... I am getting a due date of early to mid june. So maybe the doctor can help you further. The only way to know for certain is a DNA test like you said. You can get one while she is pregnant although it may cost a pretty penny or two! Good luck and if you think she is telling the truth just be there as much as you can....
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354373_tn?1299188126
nemt4paul - Did you go to the appt. today?  What did you find out?
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427097_tn?1210954367
Kelly.....no, I'm going in today.
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354373_tn?1299188126
Good luck and let us know what you find out.
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427097_tn?1210954367
Well, we went in yesterday day and came out quite disappointed.  The midwife was very short with me and didn't answer my questions sufficiently.  I tried to ask her about the difference between the LMP and ultrasound and she just wouldn’t have it.  

She kept saying they are going by the ultrasound because it’s more accurate than LMP.  I wanted to scream and say “listen here….if 9/2 is the LMP there is no way these babies will get into June.”   She just kept reiterating that the babies due date is set for the beginning of July.  

She basically said we won't know if they are Small for Gestational Age until the next ultrasound.  

I did talk to another midwife (very experienced) about our situation, however, and she said unequivocally that these babies were conceived on her next cycle.  My girl friend, however, swears that her LMP was on 9-2-07.  

The only problem with that is......I wasn't with her during her next cycle.

My gut and instinct are saying that these are my babies, but the ultrasound results aren't jiving when we were together.  

I'm very confused.  I hope to find out a lot more on March 13th......the next scheduled ultrasound.

On a positive note, the babies and the mother appear to be healthy.  No problems to speak of.

Thanks
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251790_tn?1317316467
If you ask me, mom knows best.  Your situation is difficult given that she didn't realize until 5 months but I would still go with what your girlfriend is saying, especially because your gut feeling is telling you the same thing.  Good luck on your next visit.  I think docs give way too much credit to technology and not enough to mothers intuition.
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Avatar_f_tn
Okay, personally, July does seem a bit off..however, you were going by as you said "a normal 37 week pregnancy" there is no such thing... it may BE common for twins to be born around 37 weeks, but that would not be the actual due date, since a full term baby [or babies] would be born at 40 weeks. If they ARE born at 37 weeks, as you'd presume, that would only mean they were delivered 3 weeks early.  So you're just taking off an extra three weeks that are throwing the numbers off more than they already are. So your estimations for Mid-May are off by some three weeks.
According to this right here, when you put in the date of her LMP, it says that she should be over 25 weeks, and due on June 8. [[http://www.whenmybaby.com/pregnancycalendar.php]]
The dates don't seem off to me, if she is in fact telling the truth, because I know that I conceived in early to mid September, and my baby's due date is on June 1st.
But if these babies are measuring at around 19, and 18 weeks.. that part does seem a little off... but babies tend to develop at different rates, especially twins.. And she could have ovulated a little later than normal, and the sperm that got her pregnant [assuming yours] could have lived inside her vagina/uterus for a few days, setting the dates off even a little more.

The U/S dates could be innacurate, twins tend to be much smaller than singletons, so just because they are measuring at 19, and 18 weeks.. does not mean that is how old they are, gestationally.. Although, if that were their actual gestational age, and not just a measurement from the U/S, then yes, that would put her at having conceived during her next cycle, not the one that she is stating. but it does mean that she is lying. things like these do happen. And as you already know, paternity test is the only way for a sure answer.
Good luck to you!
I hope I was atleast of some help.
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427097_tn?1210954367
Thanks for the info....I know what you are saying and thought this all through.  What is REAL is the ultrasound and LMP are a month off....period....end of story.  Now this is either due to the babies being in about the 1 percentile or they aren't my kids.

Based on a 40 week pregnancy and her LMP the due date would be June 8th.  

Based on a 40 week pregnancy and her ultrasound gestational age the due date is around July 6th.

I was using mid-May...not as the due date, but the date they will probably be born if they are my kids.  I understand the due date of a 40 week pregnancy will be early June.  Most twin pregnancies don't make it past 38 weeks....from what I've read.  

In the research I've conducted....twins’ progress at almost the same rate as singleton babies in the first two trimesters.  It's the third trimester when the growth rates start to tail off and vary.

Thanks again so much for responding.
  

  
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427097_tn?1210954367
Mommy2Tay_Cal,

in your best friends case, were the babies born closer to the due date as determined by LMP or gestational age determined by ultrasound?
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367974_tn?1286554758
As others said the DNA test would be the only way to put your mind in peace.. assumptions would only make it worse specially that the ultra sound is showing smaller babies as well as her period wasn't regular so would be hard to replay on lmp! be supportive which I am sure you are and be the father unless confirmed otherwise... best of luck
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414635_tn?1272221293
You sound like you are very well informed and I hope that these babies are yours- you sound like you'd be a good dad. The only way to know for sure will be a DNA test but I hope you continue to support your ex during her pregnancy and after no matter what the outcome is. I'm sure finding out at 5 months was quite the shock for both you and her, and I noticed she is quite a bit younger then you..be her rock through this.
Good luck!
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435139_tn?1255463991
WOW, I don't really have anything of value to add to this other than I am so impressed with your deep understanding and initiative in this ordeal!  Very 'gray' area!  I couldn't say either way!  Please keep posting-I'd be interested to see how this all plays out!  Good luck!
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427097_tn?1210954367
There has been some new information regarding the preganancy that I'd like to share.  Any comments are welcome.  This is a copy of the letter that I sent our OB before we met with him last week:

Dear Dr. ***** :

My name is ***** and I am writing this letter in regards to the pregnancy of my girlfriend, *****.  I hope to provide you with information that will be helpful in the management of her pregnancy.  We have our first appointment with you at the ***** Clinic on 3/13/08.

Here are some important details surrounding the pregnancy:  
-*****’s LMP was 9/2/07.  
-The date of intercourse was 9/15/07.  
                -***** went in for an ultrasound on 2/13/08, and learned at that time of her       pregnancy with twins.
- On 2/13/08, ultrasound dates of Twin A was 19w3d. Twin B was 18w6d.

According to LMP, the gestational age of the babies on 2/13/08 should have been 23 weeks, 4 days, a discrepancy of approximately four weeks.  The due date of our twins by LMP is 6/8/08, but by ultrasound it is estimated at 7/8/08.  From the research I've done, I understand that the later the first ultrasound is done, the less precise it is in determining the actual gestational age, but the literature all says it is within two weeks of the actual gestational age.  I also realize that growth rates may be different for twin babies as compared to singletons, however, that usually isn't recognized until the third trimester. Please correct me if those assumptions are incorrect.

***** informed me last week that she was bulimic throughout the first twenty weeks of her pregnancy.  This was hard for her to admit and she feels very guilty.  She stopped vomiting on 2/13/08; the date she found out she was pregnant.  I am doing my best to support her as we strive to have the healthiest pregnancy possible, and I know we can only control what is ahead, not what has already happened.  ***** has agreed that she needs to bring this up with you at our appointment in order to be sure the twins get all the care they need.

I am concerned about the size of the babies because from what I’ve read, gestational age and due date are usually determined by the first ultrasound. The ultrasound due date, however, is a whole month after the LMP due date.  I understand that if the babies were a whole month behind in size at 23 1/2 weeks, the twins’ growth rate lies below the 10th percentile for that gestational age and that must not be good.  With the preceding details in place, I have written some of my questions down:

Question #1- Is it possible for the ultrasound to underestimate our babies’ gestational age by 4 weeks?

Question #2- If they are small for gestational age,(maybe due to malnourishment from the bulimia) what can be done now to catch up....if anything?  

Question #3- If they are SGA, is there a way to find out if they are Intrauterine Growth Restricted?

Question #4- If the twins are IUGR; will you be able to determine whether or not they are Symmetrical Growth Restricted or Asymmetrical Growth Restricted
Based on the next ultrasound?  

Question #5- Am I overreacting?  Should I just wait until the next ultrasound for more information? When will the next ultrasound be?

Question #6- What other concerns should we have?
  
Thank you very much for taking the time to read this letter Dr. *****.  I have heard great things about you and I am looking forward to meeting you.  If there is anything that I can do, please don’t hesitate to ask or tell me.  I will do whatever it takes to ensure that ***** and the babies are as healthy as possible.

Sincerely,




me
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427097_tn?1210954367
This is some of what the Dr. had to say.....

Question #1.....He said that ultrasounds are generally more accurate than LMP at 20 weeks and that is why they will continue to use the due date as determined by the 1st ultrasound.  

He also basically said in not so many words "she must not have ovulated at that time".  In other words "she didn't conceive on the 15th of Sept.”  The thing is we only had sex on that date.  

Question #2....He said "catch up" growth is a possibility if they are behind.

Question #3....Explained IUGR....I learned nothing new about this.  He did say, however, that generally babies in the first two trimesters aren't labeled SGA because they grow at the same rates and that IUGR usually are recognized in the third trimesters.

Question #4....Explained Symmetrical VS. Asymmetrical and said that Asymmetrical is better....generally they catch up in the third trimester.

Question #5....Said we could adjust the due date and find out more at the next ultrasound.  The next ultrasound is in the process of being scheduled.  We are going to a specialist for a higher definition ultrasound.  

This is due to only one placenta being recognized in the 1st ultrasound.  He wants to see if there is only one or there are two that are fused together.

Question #6....not much else information.  Everything so far (with exception to the placenta question) seems to be healthy and on schedule.  

I still have a gut feeling that these babies are mine and the Dr.'s are just flat wrong on this one.  Most of the health professionals that I've spoken with aren't coming out and saying it.....but I'm getting the impression they don't think these babies were conceived on Sept. 15th.  

I'll continue to be there until the end.  I will know a lot more in late May or early June.  If these babies are born after June 8th, then I'd have to say they aren't mine.  I sure hope they are.  

I also thought that the most common types of identical twins “share” a placenta with two amniotic sacs….don’t they?  
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414635_tn?1272221293
WOW you are really informed and have asked some great questions to your Dr. I still think that you need to have a DNA test done where there are so many factors involved. Best of luck with everything!
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427097_tn?1210954367
I noticed that 2/3 of identical twins share a placenta.  In a small percentage of those 10% Twin To Twin transfusion can take place and that is what they are monitoring it very closely.  
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427097_tn?1210954367
went in for a Level 2 ultrasound yesterday and have some great news......both babies are in great physical condition and are growing at a normal rate from last ultrasound.  They have all organs, good blood flow and everything is great.  Identical Twin boys is the result!!!  (They are sharing a placenta....so assumption of identical).

However,

They didn't adjust the ultrasound due date and said the babies are growing at an acceptable rate (therefore ruling out IUGR babies at this point....which is GREAT.....but not for my prospects of being the father).

I'm feeling so awesome right now.....at the same time really struggling.
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456039_tn?1302663748
If you want to be the father of these children then you are. Even if the mother was with someone else and these are not biologically yours, she obviously feels that you would a better father then whoever she slept with after you, so if you want to step up and be the father then go for it. If you don't want to be the father get the DNA test and walk away if they aren't yours. You sound like you want these boys, so why not? I know it makes a HUGE difference now if they are biologically yours, but when you see them you may be happy just to have them call you Dad and never want to know for sure.
I wish you all the luck, and the mother a healthy pregnancy.
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403255_tn?1278816866
I have to say I am really touched by this whole thread. I wasn't on much in Feb when the thread started so if it hadn't been for your update I would have missed it. I DONT believe in God as such but I do think there is some reason why you have been placed in this situation. How wonderful it would be if all children had the opportunity of a Dad like you :)
xx
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427097_tn?1210954367
I don't really feel like getting into the pesonal details, however, I felt I could round out this thread by letting everyone know that I'm not the biological father.

Ultrasound dates were dead on.
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