Testing For Birth Defects

11 Replies
Jen - April 25

Next week I will be 18 weeks and the doc said I would be tested for baby birth defects. If me nor my husband have any abnormailities in our family, is this necessary? I have heard this procedure can cause all sorts of things (miscarriage, spotting, pain afterwards). Any thoughts?


2nd time mama - April 25

Hi Jen, depends where you are. here in Canada we have 2 part test - which involves an U/S and a blood test. The U/S measures the Neural Translucency NT [this is the fluid in the baby's neck] the normal range is usually <2mm. This NT and blood test only give you an estimate as to what your chances are of having a baby with a birth defect. This is done at about 12-13 weeks. The 2nd part is done at 18 weeks where again you have an U/S and blood test. These two tests combined will tell you your chances. If it's a positive meaning it's suspected that your child may have a birth defect only then do they offer an amnio - in which case there is a threat of a M/C and so forth. In you 18 week apt it should just be an U/S nothing else - if I'm not mistaken. Hope this helps you. I ended up doing only the 1st part [U/S and blood test] I then declined b/c I've heard of so many false positives - I did have an 18 week scan and thank God on the report it said there were no anomolies detected, but I didn't do the blood work. I'm leaving it up to God and His will. Good Luck to you!


CaliTrish - April 25

Hi Jen, you can refuse to have any genetic testing performed. However, birth defects are not necessarily hereditary. The screening tests consists of simple blood tests and/or detailed U/S which are safe, but they can only a__sess the risk of having a birth defect and are known for a high rate of false positive results. The diagnostic tests, such as CVS or Amniocentisis, do have 1-2% risk of miscarriage. So, you have to weigh the risk of not knowing to possibly losing the baby. At 18 weeks, you doc is probably thinking of the Expanded AFP Screen (a.k.a. Maternal Serum Triple Screen) or an Amnio. If you have concerns, I would contact your doc for more info. I had the Combined Screen like 2nd time mama. My odds improved enough that I chose not to have an amnio eventhough I am over 35.


Kara H. - April 25

What you doctor is probably talking about is the triple screen or the quad screen blood test. It's just the same procedure as any other blood test. They usually do it between 16-18wks. It is an optional test as some people, due to religious beliefs, don't want to know their ratio of having a baby with a genetic problem. Even though we would never interupt a pregancy, we did do the test just so we could rest easier knowing our baby was healthy. Our ratio was unbelivably low. Had it been a high ratio they would have offered us an amnio, which does carry some risk of miscarrige, but they only offer it if something comes up on your blood test.


EricaG - April 25

Jen, I refused the tests because even if we found out something was wrong, we weren't going to terminate the pregnancy. I think they just give you a ratio of how likely your baby is to have certain problems. I thought, why worry? Anyway, this was just me. Good luck :o)


sa__sifras - April 25

I did the same as EricaG. We were told that unless there was a chance for us to want to terminate the pregnancy if something was wrong(which there are false positives with some things too)there was really no point other than to just prepare ourselves.


Taffy - April 25

Jen, I'm having my AFP test on Thursday. If the results aren't good it doesn't mean that I would definitely terminate the pregnancy but I would however like to know in advance if I had a child with special needs. My brother is mentally handicapped and I have grown up knowing what its like to be with and love someone who is handicapped. I would never wish that he wasn't there. But if I have to face the possibility of bringing up a handicapped child I would prefer to know in advance to mentally as well as practically prepare for their arrival. If your tests are simple blood tests there is no harm to the baby so, why not? Hope it helps to see another point of view. Good luck. :)


numba1cutie6t9 - April 25

the blood tests have a high false positive rate. just keep that in mind.


Kara H. - April 25

The test also checks your ratio for spinal bifida. Which had it came back positive, I would have made a difference in which hospital to deliver at.


ThePezChick - April 25

I had the AFP bloodtest this past Thursday and am having the level II ultrasound Friday. My husband and I plan to keep the baby regardless, but I wanted to know so I could prepare ahead of time in case there was a disability such as Down Syndrome or any other abnormality. There are tons of support groups out there and each syndrome, disorder, etc. has its own specific set of circ_mstances. For instance, infants with DS can often have a difficult time suckling. I don't anticipate anything being wrong, but I wanted to know regardless. Chances are that all of our babies are perfect, so I'm not worrying.


Erynn21 - April 26

I opted out of the the AFP test a couple of weeks ago, it false positives a lot. I had just had an u/s and everything looked great. My dc. is a very no nonsense lady and has told me from day one any test is my choice, I researched the AFP test and decided not to take it.


Ddvinson3 - April 27

On April 11 I had my last appt and it I was about 17 weeks I think and I declined the tests. All they were, were the blood test to see if I was at risk. But honestly I will prepare myself for the worse and just want to enjoy my pregnancy. I've heard to many horror stories of the risk coming back really high and then the mom getting the amnio and everything turned out fine. I just don't want to have to go throgh that. But it's really up to you. I worry to much though.



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