C.M.
Congrats on the new baby and on nursing for so long. However, I must offer some caution. While breastfeeding while pregnant is not harmful to your baby, it is very hard on your body. Your body is working overtime to create and develop this new life while the little one you already have is also depleating you of nutrients that your body needs right now. At 18 months, she no longer needs to nurse. She is getting plenty of nutrients from the food that she eats everyday and does not need the supplement of breast milk. At this point, she does it out of habit more then out of need. I would suggest this would be a good time to ween her. That doesn't mean that you can't hold her and snuggle her anymore. Just let her drink cows milk or whatever kind of milk you prefer while you do the snuggling before bed. If she is down to just nursing at bedtime, it shouldn't be that hard to go ahead and break the habit. In the long run, all three of you will be healthier.