Genital & Urinary Symptoms in Babies

Blood in the urine (hematuria) can appear as pink, red, brown, or tea-colored urine. In babies, it is important to first rule out false positives: urate crystals (orange/pink in newborns), food coloring (beets), and vaginal bleeding in newborn girls (pseudomenses — normal). True hematuria always requires medical evaluation to determine the cause, which ranges from urinary tract infections to kidney problems.

Normal baby urine is pale yellow to almost clear. Dark urine (deep yellow, amber, brown, or tea-colored) in babies most commonly indicates dehydration (concentrated urine) but can also suggest liver problems, blood in the urine, certain medications, or metabolic conditions. In newborns, brick-red urate crystals in the diaper are common and harmless but can be mistaken for blood.

Pink, orange, or brick-red staining in a baby's diaper is most commonly caused by urate crystals — a normal byproduct of uric acid concentration in newborn urine. These are sometimes called "brick dust" and are very common in the first week of life before breastfeeding is fully established. While usually harmless, persistent urate crystals beyond the first week may indicate the baby is not getting enough milk and becoming dehydrated.

Genital swelling in newborns is very common and usually caused by maternal hormones and/or birth-related fluid accumulation. In boys, scrotal swelling from hydroceles (fluid around the testicle) is extremely common and usually resolves by 12 months. In girls, labial swelling from maternal estrogen is normal in the first weeks. Beyond the newborn period, genital swelling can indicate hernias, infections, torsion, or trauma requiring prompt evaluation.

Labial adhesion (labial fusion or synechia) occurs when the inner labia minora stick together, partially or completely covering the vaginal opening. It affects up to 2% of girls, most commonly between 3 months and 6 years of age. It is caused by low estrogen levels (normal in prepubertal girls) combined with mild inflammation. Most cases are asymptomatic, require no treatment, and resolve spontaneously with puberty.

Parents commonly have concerns about their baby boy's penis including foreskin issues, circumcision care, swelling, erections, or appearance. In uncircumcised boys, the foreskin is naturally adherent to the glans at birth and gradually separates over years — forceful retraction should NEVER be attempted. In circumcised boys, normal healing includes yellow-white discharge at the circumcision site and mild swelling for the first week.

Baby urine is usually nearly odorless or mildly sweet-smelling. Strong-smelling urine is most commonly caused by concentrated urine (dehydration) or dietary changes, but can also indicate a urinary tract infection (UTI). UTIs in babies can be difficult to detect as the only sign may be fever, irritability, or foul-smelling urine. Certain rare metabolic conditions also produce distinctive urine odors.

An undescended testicle (cryptorchidism) occurs when one or both testicles have not moved down into the scrotum by birth. It is the most common genital abnormality in baby boys, affecting approximately 3-5% of full-term and up to 30% of premature boys. Many undescended testicles descend spontaneously by 3-6 months of age. If still undescended by 6 months, surgical correction (orchidopexy) is recommended by age 12-18 months to preserve fertility and reduce cancer risk.