Babies — breastfed or formula-fed — with parents who smoke are more likely to experience pneumonia, asthma, bronchitis, ear infections, sinus infections, eye irritation, and croup than babies who aren't exposed to smoke. (Babies can be exposed through breast milk, being in the room with someone who is smoking, or even by inhaling the irritants left hanging around on clothes and furniture.) Babies with smoking parents are also more likely to die of SIDS, more likely to be colicky, have lower levels of HDL (good cholesterol), get sick more often, and are more likely to smoke when they get older.
Is your baby safer if you stop breastfeeding because you're smoking? Most experts say no. If you choose to switch to formula, baby is still affected by your smoking…plus he doesn't receive all the health benefits of breast milk. So, in essence, smoking and breastfeeding is better for baby's health than smoking and formula feeding.
Protect baby by getting help to kick your addiction, or at least try to cut back. The fewer cigarettes you smoke, the lower the risks for you and baby. And if you do continue to smoke, don't smoke around your baby. (And don't let others smoke around baby either.) To lessen the amount of nicotine that baby gets through your milk, don't smoke during feedings, and wait as long as possible between smoking and breastfeeding.
You'll need to learn as much as you can about building and maintaining your milk supply, since smoking can lead to lower milk production, problems with letdown, lower levels of prolactin (the hormone that helps fill your breasts with milk), and early weaning.