Gynecomastia in neonate is seen due to:
a. Mother's estrogen(Ref: Nelson 20/e p 2742)Transient gynecomastia occurs in 60-90% of male newborns secondary to exposure to estrogens during pregnancy.Breast development may be asymmetrical and galactorrhea is seen in 5%.Most cases resolve within 4-8 wk of birth, but a few can last as long as 12 mo.
Mother's estrogen
Mother's progesterone
GnRH
Gonadotropins
Endocrinology