If I were you, I would not do the amnio. I wouldn't want to risk a miscarriage or other complications, no matter how slight the chance. You've made it so far, and it sounds like they're pretty confidant there are no neural tube problems, so that is great news.
I've had two small for gestational age babies and most likely this one will be too (they are monitoring me very closely, as they did with my boys). Both my boys ended up perfectly healthy, just very tiny and skinny! With my first they said my placenta was unusually small. Don't know why, don't know how to prevent again, and don't know for sure that's why baby was so small but probably why. May just be the way my body makes babies! PM me if you would like more details or want to talk more about it. Any issue can make you nervous (it did me!), but most likely everything will turn out perfectly fine!
ETA: the only thing they did differently for babies #2 and #3 after my first SGA baby was have me take one baby aspirin per day throughout my entire pregnancy (stopping it just a few weeks before due date). Apparently there are some studies that indicate it can increase blood flow to the placenta, thus helping provide more nutrients to the baby. My baby #2 was slightly larger than baby #1, so maybe it did help. They also make me start eating tons (milkshakes, ensure, etc.) toward the end so that baby is sure to be getting enough nutirition to fatten up :) And 1 week behind could be nothing - baby could catch up on her own for sure. My first was measuring 4 weeks behind for the last two months of my pregnancy. And as long as they continue to progress, even if small, they'll leave em in and not induce early.
who I absolutely adore, and now is here!
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