Here's the deal - the screening only detects 90% of the issues, and can also give a 3-5% false positive. So it's not a diagnostic test, just a screening. With that in mind:
My odds for Downs, based purely on age, was 1/64. After the test, the odds are now 1/1261
My odds for Trisomy 13/18 based on age was 1/116. After the test, the odds are now 1/1742
The genetic counselor was very enthusiastic - she said these are really good screening results. I'm thrilled, too, but now I have the dilemma - do I get the amnio or not? I asked the counselor and she said that women who have results this good mostly do not get the amnio, but it's a very personal decision.
- First, I don't have to make up my mind right away, I have several upcoming screens scheduled. I easily have until week 20 to decide (7 more weeks), and I can even wait until week 22, but that could be pushing it.
- July 9 - sequential screen. This is a blood test that will further refine the odds, going up to about 93% accuracy for downs, and also screens for spina bifida (80% accuracy). She said this probably won't change my odds much, since my first screen shows such small odds
- Aug 6 - genetic ultrasound. This is a very long and detailed ultrasound that I'm really just doing so I get another ultrasound! The accuracy is less than the other 2 screens, so it won't tell me anything more, but will help to confirm the results using another method.
- Chance of miscarriage from amnio - 0.3% to 0.5%
- Chance of downs/tri based on new odds - less than 0.1%
- Would I terminate the pregnancy if I knew the baby had downs or trisomy? yes
- Could I live with myself if an amnio caused a miscarriage and the baby was fine? no
So my happiness is tempered a bit by having to decide how I'm going to roll the dice. Do I eliminate the chance of miscarriage, but risk downs/trisomy? Or do I know for sure about downs/trisomy and risk miscarriage? If I skip the amnio, will I be worried all pregnancy? What would I do if I gave birth to a baby with downs?
At my age (will be 41 at delivery), I was fully expecting to be at a higher risk level and going ahead with the test. But now, the risk of a chromosomal problem is significantly less than the risk of miscarriage. I'm a numbers girl, so my gut is telling me not to do it, but I'm very interested to hear any other experiences, opinions, or thoughts!
PS - had my 2nd OB appointment yesterday. Very quick (except for the 45 minute late doctor!). Couldn't find the heartbeat on the doppler, but found it right away on the ultrasound (giving me yet another picture!). The funny thing is - I wasn't nervous when she couldn't find it on the doppler - I think I'm feeling more confident!