OOPS, forgot a few other things I like to look at, that might affect infant's suck:
1) how are the infants fetal heart tracings? were there lots of of compromising situations like deep variables or; bradycardias, or were there those ominous late decels?
2) what are mom's breasts and nipples like? While we never
say it to a mom, some breasts/nipples are easier for an infant to learn on than others. Protruberent nipples are able to be put into infant's mouth, to some extent, and don't get dropped/pushed out while the baby is coordinating other facets of the suckling.