Can I keep nursing if I'm pregnant again?
Continuing to nurse likely is safe for you, your son and your baby in utero. A few caveats: Since breastfeeding burns calories and requires more fluids, you must eat and drink enough to stay well-hydrated and nourished and gain adequate weight. Also, breast stimulation in the last six weeks of pregnancy can lead to uterine contractions, so if there are concerns about preterm labor, your obstetrician may want you to stop nursing.
Keep in mind that you probably will experience a significant decrease in milk production because your body is working to maintain an increased volume of blood and other fluids. But if your son is getting significant nutrition from other foods, nursing can continue to be a wonderful source of comfort for both of you.