July 31, 2005
permalink Amnio - "We can't use the blood / biochemistry screen for you because you are diabetic"

Why am I having an amnio? I really don't want to sound too flippant about this because believe me I have agonised and agonised over it, mostly while I was extremely ill with the flu which was when I had to make my decisions about it and when I got my nuchal results. It's been a roller coaster ride.

It started off when my nuchal result came back 1:397 chance of Down syndrome. Results over 300 are considered low risk where I got my nuchal done. The test has 80% accuracy ie of baby's born with Down syndrome 1 in 5 would not have been picked up by the test. My ob figured this was pretty good and said she wouldn't recommend any further testing, but if I was extremely anxious she would support me as it would reduce my anxiety. She made sure I understood there was a 1:200 risk of miscarriage from the amnio procedure. She said that the way she looked at it was: go ahead with the procedure only if the risk of miscarriage from it is lower than the risk of birth defect. But I reckon it's much more complicated and obviously personal than that.

I was also a bit perplexed that my obstetrician had ordered blood tests to go with the nuchal but at the ultrasound clinic they did not use the blood test results for me because I was diabetic! They did not combine my nuchal with the blood test results (which is routinely done now to increase the predictive accuracy of the nuchal for women I think to about %90-95). When I'd been pregnant last time I'd gone out of my way to get this blood test done and it was combined with my nuchal screening. I'd therefore felt reassured about the accuracy levels.

If they weren't going to be able to use them, why did my ob get me to have the blood test done? An oversight I now believe, but at the time I got the feeling some places did use the blood test results for diabetics for the combined risk assessment and other places wouldn't. The place I got my nuchal done said it was their policy to follow the guidelines of the organisation who developed the nuchal screening software and they had deemed the blood test results for the PAPP-A first trimester screening unreliable for people with diabetes. I believe the readings are more likely to give false positives.

Anyhow, the nuchal result of 1:397, although good, was for me pretty close to high risk (under 1:300). The last time I was pregnant my risk was about 1:2000 and the greater risk this time was only partly due to age. For my age in general (thirty-seven and eight months) there is apparently a 1:113 chance of having a baby with Down syndrome.

With a 20% uncertainty to factor in because my risk did not include the biochemistry I felt after thinking it through a lot that there was too much uncertainty for me.

I went to my GP to discuss it and he agreed that I could try another maternal and fetal ultrasound place to see if they would use my biochemistry. Over the phone the doctor asked me a series of questions about my weight and my diabetic control and said he would run my numbers through his software to give me the combined risk because my diabetes was in such good control. I thought this was great. More information to go on.

But when I fronted up for the appointment he phoned his friend, a biochemist, to discuss my results. Then he explained that one of my levels was over 4 times the multiple of the median which made me very high risk. He felt that not to use my blood test results given the very high risk would be negligent. He mentioned figures like 1:10 and 1:20 risk for Downs. Wow. My ob later told me to be aware that false positives are common with the blood test (and possibly more common in women with diabetes?), but still, this doctor's comments were enough to convince my partner and I that there was too much uncertainty for us and we would feel better having an amnio.

Still not an easy decision ...

I felt bad about thinking I would terminate if I found I had a baby with Down syndrome. I have a good friend who has a little girl with Down syndrome, and I see people at the local playground and McDonalds who have Down syndrome and seem to be coping okay. But I also know that other people with Down syndrome have severe, quality-of-life limiting disabilities, some need to be tube fed, others suffer with leukaemia on top of hearing and visual impairment. My partner and I were in the midst of a very stressful time just trying to look after our toddler whilst we were all very sick with the flu and I wondered whether our relationship would hold up with a child with a severe instance of Down syndrome?

Of course, all this in the context of the fact that Down was still quite unlikely and if the truth be known, I was much more concerned about what damage could have been done to our unborn child due to my diabetes.

There were many times when I really felt that being pregnant with type 1 diabetes was a form of mind torture. I felt completely unethical and unworthy.

I also thought about the possibility of my own health deteriorating in the medium term future due to diabetes and just how much ability I would have (or my husband or daughter would have) to care for me and a child/sibling with a disability.

So I guess, I was now going along the lines I thought I would. Getting a lot of testing done. Hoping to rule things out.

The thought of potentially losing a healthy baby due to miscarriage because of the amnio was also not something I took lightly. We had been very lucky conceiving easily with both pregnancies, but this pregnancy so far, especially with the flu, but also with the diabetes emotional roller-coaster, had been very emotionally and physically difficult. How easy would it be to try again? Would it even be ethical?

Anyhow, amnio is what we have decided to do. So fingers crossed for Thursday...

Posted by patton at July 31, 2005 07:25 PM
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