Key takeaways: Hormones from pregnancy can cause swollen breasts in newborn boys and girls and white or blood-tinged vaginal discharge in girls. These are normal and fade within weeks. Don’t squeeze the breasts. Redness, warmth, or fever needs a call.
Newborns are exposed to high levels of their birthing parent’s hormones during pregnancy. After birth, these hormones can cause some surprising but harmless changes.
Swollen Breasts (Neonatal Breast Hypertrophy)
- Both boys and girls can have swollen breast buds in the first weeks.
- Sometimes a small amount of milky fluid leaks from the nipples, historically called “witch’s milk.”
- Swelling usually goes away within weeks to a few months.
What to do: nothing. Don’t squeeze or massage the breasts, which can irritate them and increase the risk of infection.
Vaginal Discharge in Baby Girls
- White, mucus-like discharge is common in the first weeks.
- Some baby girls have a small amount of blood-tinged discharge, sometimes called a “mini-period” or pseudomenses, in the first week or two. It’s caused by the drop in hormones after birth.
- The labia may look swollen.
What to do: gently wipe front to back during diaper changes. You don’t need to remove all of the white discharge.
Other Hormone Effects
- Baby acne on the face.
- Swollen genitals in boys and girls.
When to Call the Doctor
Call your baby’s doctor if:
- A breast becomes red, warm, firm, or painful, especially with fever or poor feeding. This could be a breast infection (mastitis or abscess) that needs treatment.
- Vaginal bleeding is heavy or lasts more than a few days, or starts after the first couple of weeks.
- Breast swelling or discharge continues for several months or appears later in infancy.
- Your baby has a fever of 100.4°F or higher (rectal) in the first 3 months.
The Bottom Line
Swollen breasts and vaginal discharge in newborns are common, hormone-related, and temporary. Leave them alone and call the doctor for redness, fever, or heavy bleeding.
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Sources
- Altmann TR, Hill DL, eds. Caring for Your Baby and Young Child: Birth to Age 5. 7th ed. American Academy of Pediatrics; 2019.
- Lewis ML. A comprehensive newborn exam: part II. Skin, trunk, extremities, neurologic. Am Fam Physician. 2014;90(5):297-302.
- American Academy of Pediatrics. Breast swelling and discharge in newborns. HealthyChildren.org. https://www.healthychildren.org
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
