C.H.
Your doctor may be wrong. Mine was. My third child was diagnosed with ABS in utero and his life would have been very different had we listened to the first doctor rather than getting a second opinion. ABS is very rare, especially an in-utero diagnosis. There just isn't good info out there. We would up going to the Fetal Care Center in Cincinnati, OH and they were able to perform surgery that saved our son's life. Not all cases of ABS are life threatening, but you need to get a second opinion.
There is good info about it at http://www.amnioticbandsyndrome.com/ and the Fetal Care Center in OH is at http://www.fetalcarecenter.org/. There are a couple others scattered about the country, but this is the one I'm familiar with, as they took care of us.
There are NO known environmental or genetic links to ABS. You didn't do anything wrong at all. Also know that you are not alone. www.fetalhope.org has resources for parents who receive a diagnosis of a fetal syndrome. You can also check out my son's story of surviving ABS at www.caringbridge.org/visit/levimatthew.
Also, googling while I was pregnant and seeking a second opinion is why my son is alive and has two functional hands.