Amnio

[babymama73]

I am 36 and my husband has mental retardation on his side of the family.  Our specialist talked us out of our scheduled amnio at our last visit, stating that the odds of a chromosomal defect were only 1 in 4000 after our frist trimester screening came back negative.  I can't find any research to substantiate her stat. Is this standard practice for a doc?  Should I still have the amnio done?

[SoCalTricia]

Your anxiety is understandable - and totally normal! The first trimester screening is a calculation of your risk of having a baby with a chromosomal problem. They take the measurements from the ultrasound (femur length, head circumference, nuchal fold, distance between the eyes, etc), the results of the mother's blood test (certain hormones and protein levels, I believe) and combine those measurements with mom's age. From that, they get a risk factor. So, according to your doctor, your risk factor is 1 in 4000 - which is EXCELLENT. Even better than the average pregnant woman, I believe. So, if you gave birth to 4000 children, only one would have a problem.

Now, the first trimester screening is an estimate - nothing definate. The only way to know for SURE nothing is wrong is the amnio. BUT, the risk of having a miscarriage due to the amnio is about 1 in 300. So, you're more likely to have a miscarriage by having an amnio, than you are to have a baby with chromosomal abnormalities. That's why my husband and I decided not to do the amnio - my risk was something like 1 in 1000...probably a little higher than yours because I'll be 41 when the baby is born.

The only thing I'm wondering...you said your husband's family has "mental retardation." That can come from many things, so I'm wondering if the amnio would even help you with that problem. Amnio check for chromosomal issues, i.e. Down Syndrom, Trisomy 13, etc. It doesn't check for brain structure issues or developmental issues that would cause retardation. So, it may be that an amnio would be an unneccesary risk, and that might be what your doctor was thinking. Try to find out what the "retardation" issues in your husband's family stem from, and you'll have a better idea how to calculate your risk.

I have a feeling that you'll be just find...but you're at that point in your pregnancy where you're worrying about everything! Take a deep breath and relax...  :-)

Tricia

[martikadragoon]

babymama~YES it's standard practice. they won't push an amnio unless your chances are around 1:500 or less.... I have a son with down syndrome AND my rare genetic disorder (skin disorder) The skin disorder is a %50 so I'm having an amnio with each pregnancy.

You can request a Level 2 ultrasound to check for any soft markers of Down Syndrome or T18. That'll give you a much better picture and is DEFINITELY lower risk than an amnio. Don't put yourself thru an amnio if you don't have to k?