A potential answer could be teratogens. It means "an agent or factor that causes malformation of the embryo".
In this case, the lead would contribute to the accumulation of lead in the unborn child's system causing it to have birth defects including but not limited to smaller head sizes, and damage to the brain, kidney, and nervous system.
The alcohol could bring about conditions such as Fetal Alcohol Syndrome and various other birth defects.