One of the scariest situations I've encountered is moms who do significant
amounts of  marijuana.  The THC reduces prolactin levels and makes they
spacey. So their kids don't gain, and they aren't worried about it.  Also,
THC accumulates in milk because of the high milk:plasma ratio and high lipid
solubility (brain is 55% fat!) giving their babies a double whammy and
probably making the babies spacey too. With reduced prolactin, they don't
make as much milk and they aren't as worried about it as when prolactin is
high and the "mother instinct" is fully operational.
Linda Smith