Management of Infant Gynecomastia from Hormonal Influences
Infant gynecomastia caused by maternal hormones is a physiologic, self-limited condition that requires only reassurance and observation—no treatment or intervention is necessary.
Understanding the Condition
Physiologic gynecomastia in newborns is extremely common and benign, occurring due to transplacental transfer of maternal estrogens 1, 2, 3. This represents one of three normal peaks of gynecomastia in males (newborn period, adolescence, and older age) 1, 3.
Management Algorithm
Step 1: Confirm Physiologic Gynecomastia
- Verify the infant is a newborn or young infant (typically presenting in first weeks to months of life) 1, 2
- Confirm bilateral, soft, rubbery breast tissue enlargement directly under the nipple 4
- Rule out galactocele (milk-filled cyst), which can occur as a complication of neonatal genital crisis and presents as a discrete mass 5
Step 2: Exclude Pathologic Causes
Critical red flags requiring immediate specialist consultation:
- Bilateral nonpalpable testes in a phenotypic male newborn—this mandates urgent evaluation for disorder of sexual development (DSD), particularly congenital adrenal hyperplasia, which can be life-threatening 6
- Ambiguous genitalia or hypospadias with gynecomastia 6
- Unilateral, hard, fixed, or eccentric mass (concerning for malignancy, though extraordinarily rare in infants) 4
Step 3: Provide Reassurance and Observation
- Explain to parents that this is a normal, temporary condition 1, 2
- The breast enlargement will spontaneously resolve, typically within weeks to months as maternal hormones clear from the infant's system 1, 2, 3
- No imaging, laboratory testing, or treatment is indicated for typical physiologic infant gynecomastia 4, 2
What NOT to Do
Common pitfalls to avoid:
- Do not order ultrasound or other imaging studies—these are unnecessary and can lead to additional unnecessary interventions 4
- Do not measure hormone levels in typical cases of newborn gynecomastia 2
- Do not prescribe medications or recommend surgical intervention 1, 2
- Do not circumcise male infants with bilateral nonpalpable testes until DSD workup is complete 6
When to Refer
Immediate specialist referral is required for:
- Any phenotypic male newborn with bilateral nonpalpable testes (potential DSD/congenital adrenal hyperplasia) 6
- Gynecomastia with ambiguous genitalia or other genital anomalies 6
- Persistent or progressive breast enlargement beyond the expected neonatal period 2
- Suspected galactocele (discrete cystic mass rather than diffuse glandular tissue) 5
Expected Natural Course
Physiologic gynecomastia in newborns is self-limited and resolves spontaneously without intervention 1, 2, 3. The condition occurs in approximately 25% of cases as a benign physiologic phenomenon 3. Parents should be counseled that resolution typically occurs within the first few months of life as maternal hormones are metabolized and cleared from the infant's system 1, 2.