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427097 tn?1210954367

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.    


27 Responses
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.
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.
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.
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.
Avatar universal
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.
427097 tn?1210954367
Ian--Yes this was her first ultrasound.  

Mommy2Tay-Thanks....that's good info.
427097 tn?1210954367
Thanks for all the comments....I'm going in tomorrow.
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....
354373 tn?1299188126
nemt4paul - Did you go to the appt. today?  What did you find out?
427097 tn?1210954367
Kelly.....no, I'm going in today.
354373 tn?1299188126
Good luck and let us know what you find out.
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.

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