Pregnancy has a way of making moms think of weaning, especially if it turns breastfeeding into an uncomfortable experience. It is important that you take your own needs into account with breastfeeding decisions.
Many moms begin by reducing the duration of feeds (we’ll nurse to the count of 10, or for the length of the ABC song). Moms can often stretch out the time between feeds by engaging in activities outside or exciting things like crafts inside. With honest communication you can talk with your child about the reductions without fueling sibling rivalry (“Mama’s num-nums have boo-boos right now” during pregnancy, or after the baby comes “You had num-nums all the time when you were a baby, too. Now you can eat other foods as well as num-nums.”).
See also: “Love, Limits and Tandem Nursing” by Hilary Flower, from New Beginnings, May-June 2003, pp. 86-90.