Gestational Age?

[nemt4paul]

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

[KellyA74]

nemt4paul - Did you go to the appt. today?  What did you find out?

[adawning4]

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....

[nemt4paul]

Thanks for all the comments....I'm going in tomorrow.

[nemt4paul]

Ian--Yes this was her first ultrasound.  

Mommy2Tay-Thanks....that's good info.

[Ian2008]

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.

[Mommy2Tay_Cal]

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.