What causes per vaginal (per vaginal) bleeding in a newborn?

Vaginal Bleeding in Newborns: Causes and Evaluation

Primary Cause

Vaginal bleeding in newborns is most commonly a physiological phenomenon caused by withdrawal of maternal estrogens after birth, occurring normally in a subset of female infants during the postnatal period. 1, 2

Common Etiologies

Physiological (Most Common)

• Hormonal withdrawal bleeding represents the most frequent cause, resulting from the abrupt decrease in maternal estrogen levels after delivery that the infant was exposed to in utero 1, 2
• This typically occurs within the first few weeks of life and is self-limited 2

Pathological Causes to Consider

Local/Anatomical Lesions (54.7% of cases in one series):

• Müllerian anomalies, particularly uterus didelphys, can cause heavier-than-expected bleeding due to relatively larger amounts of endometrial tissue in two uterine cavities 1
• Trauma to the genital tract 2, 3
• Genital tumors including hemangioma of the vulva, sarcoma botryoides of the vagina, or ovarian tumors (rare but serious) 2, 3
• Foreign bodies or parasites (leeches reported in endemic areas) 3

Hormonal/Endocrine Causes (18.6% of cases):

• Congenital adrenal hyperplasia can present with vaginal bleeding, particularly after glucocorticoid treatment initiation, due to altered maturation of the hypothalamic-pituitary-ovarian axis 4
• Precocious puberty (may be associated with hypothyroidism) 3
• Functional ovarian cysts causing transient estrogen production 4, 3

Hematologic Disorders:

• Coagulation defects such as hemophilia, von Willebrand disease, or disseminated intravascular coagulation should be considered if bleeding is excessive or accompanied by other bleeding manifestations 5

Diagnostic Approach

Initial Assessment

• Assess hemodynamic stability first - determine if bleeding is physiological spotting versus pathological hemorrhage 6
• Perform external genital examination looking for trauma, discharge, lesions, and masses 7
• Never force examination or perform digital vaginal examination in prepubertal children - this is always contraindicated and traumatic 7

Red Flags Requiring Investigation

• Heavy or prolonged bleeding beyond typical withdrawal bleeding 1
• Palpable abdominal mass on examination 7
• Associated signs of virilization or precocious puberty 4, 3
• Bleeding accompanied by other sites of hemorrhage (suggesting coagulopathy) 5

Imaging and Laboratory Evaluation

• Transabdominal ultrasound should be routinely considered for abnormal vaginal bleeding in newborns to evaluate for Müllerian anomalies, ovarian cysts, or masses 1
• Ultrasound can identify uterine enlargement, ovarian cysts, or anatomical abnormalities that may not be apparent on external examination 1, 4
• If coagulopathy is suspected, obtain coagulation studies, but interpret with caution using neonatal-specific reference ranges with hematology consultation 5
• Consider hormonal evaluation (FSH, LH, estradiol, 17-hydroxyprogesterone) if endocrine etiology suspected 4

Clinical Pitfalls

• Do not assume all newborn vaginal bleeding is physiological - while most cases are benign withdrawal bleeding, serious conditions like tumors or congenital adrenal hyperplasia can present this way 1, 2, 3
• Avoid digital vaginal examination in prepubertal children as it is inappropriate and can cause additional trauma 7
• Traditional coagulation testing must be interpreted using neonatal-specific reference ranges, as normal values differ greatly from older children and adults 5
• Early diagnosis of Müllerian anomalies facilitates timely intervention and screening for associated conditions 1