My wife is pregnant and breast feeding a 7month old child.any consquences?

Breast feeding : Breast feeding while pregnant is fine as long as she is eating enough extra calories to both make milk and allow the fetus to grow. Pre-natal vitamins will be important as well. You wife may or may not notice a decrease in supply. By 7 months your baby should be on other foods in addition to breast milk which will help as well. Check with your wife's dr. & your baby's dr about growth.