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Causes of a Swollen Breast in a Baby

author image Carol Ann
Known as the trainers' trainer, Carol Ann, has become one of the country's leading fitness educators. Combining national fitness certifications and a master's degree in exercise science from Middle Tennessee State University, she has achieved a 20-year career in the fitness industry. As the owner of Studio Group X Inc., she provides cutting edge personal training, consulting, freelance writing and speaking engagements.
Causes of a Swollen Breast in a Baby
Swollen breasts in babies are usually a normal condition. Photo Credit baby image by Ilya Postnikov from <a href='http://www.fotolia.com'>Fotolia.com</a>

A swollen breast is a common condition that occurs in babies, both male and female. One or both of a baby's breasts may become swollen, firm and lumpy within a week after birth. Although this condition may seem peculiar, the swollen breasts usually shrink within a few weeks or months of life. Understanding the causes of this condition helps ease concern for anxious new parents.

Mother's Hormones

Causes of a Swollen Breast in a Baby
The mother's hormones pass to the baby causing swollen breasts. Photo Credit baby image by Fabio Barni from <a href='http://www.fotolia.com'>Fotolia.com</a>

While in the womb, a baby is exposed to surging hormones that a mother produces during pregnancy. These hormones are passed along to the baby and remain within the baby after birth. Maintaining excess levels of hormones such as estrogen and androgens can cause the baby's breasts to swell. Sometimes only one breast will swell. When there is no more exposure to the hormones, the breast tissue will begin to shrink and become flat. This may take days, weeks or a few months. A milky substance called "witches milk" may leak from the nipples but will cease after a few days or weeks.

Breast Buds

Causes of a Swollen Breast in a Baby
Lumps and enlarged breasts can be noticeable at birth. Photo Credit baby image by Tatyana Gladskih from <a href='http://www.fotolia.com'>Fotolia.com</a>

According to pediatrician and author Dr. Alan Greene, swollen breasts in babies can be due to breast buds or lumps under the nipples. These lumps are mature breast tissue that can even secret milk. Breast buds can occur in both male and female babies and will diminish over the first few months of life.


Causes of a Swollen Breast in a Baby
A physician should be contacted if an infection is suspected. Photo Credit baby image by Anna Chelnokova from <a href='http://www.fotolia.com'>Fotolia.com</a>

In very rare cases, the swollen breasts in a baby are due to mastitis, or an infection of the breast tissue. If the breast or nipple looks red, tender or has a colored discharge other than a milky substance and the baby has a fever, a pediatrician should exam the baby for infection. Parents are advised not to squeeze or massage the swollen breasts, for this will only cause irritation and may lead to an infection.

Breast Feeding

Causes of a Swollen Breast in a Baby
Breast feeding may cause continued breast enlargement. Photo Credit mother holding baby #21 image by Adam Borkowski from <a href='http://www.fotolia.com'>Fotolia.com</a>

Breast feeding can contribute to the baby's breasts swelling due to the continuance of the mother's hormones passing to the baby. While breast feeding may also contribute to prolonged breast enlargement and baby milk production, temporary or permanent weaning is not recommended.

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