First things first: yes, you can continue to breastfeed during pregnancy in most cases. However, if you are advised by your doctor to avoid sexual intercourse, or are at risk for preterm labor, then you might consider weaning.
The most important thing to pay attention to during this time is your diet. Eating a healthy diet will prevent draining your body’s stores of nutrients. You will want to stick to calorie recommendations – 500 extra calories while breastfeeding and an extra 350 in the second trimester (450 in the third). That’s all in addition to your normal calorie intake.
The most common fear of breastfeeding during pregnancy comes from the uterine contractions that occur while nursing. These contractions are harmless to your growing baby. Oxytocin, the hormone released while nursing and the cause of the contractions, is not released in a high enough concentration to open the cervix just from nursing. Comparable levels of the chemical are also released during sexual intercourse.
The decision to breastfeed during pregnancy is a personal one and should be made with great consideration. In some cases, weaning a child will not be worth the stress while pregnant. Certain pregnancy symptoms may make the decision for you. The level of fatigue that some women experience might become a deciding factor, although lying down while nursing can help. Nausea and increased nipple sensitivity are also common deterrents for continuing to nurse. Breathing exercises or distraction are common methods of overcoming painful periods. Feelings of arousal from nipple stimulation during pregnancy are not uncommon and can drive many women to feel uncomfortable nursing, but there is nothing inherently wrong with these sensations.
The baby may decide to quit too. Sometimes milk supply drops during the fourth or fifth month of pregnancy and the composition and taste of the milk will change throughout your pregnancy. Your baby may just naturally decide to wean. However, once you give birth, your toddler may decide she wants to breastfeed again. Many women find that nursing in tandem fulfills both their children’s needs.
The choice to continue nursing is highly individualized – the right choice for you might not be the right one for someone else. Overall, the decision to breastfeed while pregnant is not a medical question, but a personal one.
Have you ever nursed while pregnant?
Breastfeeding during Pregnancy [La Leche League]
Nursing through Pregnancy [La Leche League]
I'm Pregnant and Still Nursing My Toddler--Must I Wean Now? [La Leche League]