What is the chance of having consecutive children succumb to sids?

Extremely low: The studies on this are limited but if anything it seems as though the chances of a second child succumbing to sids appears to be lower than the general risk.

5- 6 folds incresed: Siblings of sids victims have a 5-to-6-fold increased risk of dying of sids. Twin siblings have a two-fold increased risk of sids. However, the risk that a second child will die as a result of sids remains <1% for most families. You could get more info from the links: http://www.Uptodate.Com/contents/sudden-infant-death-syndrome-sids-beyond-the-basics http://sids-network.Org/experts/subch1.H.