Umbilical and Inguinal Hernias — Making Sense of the Bulge

Lead

"The belly button is sticking out." "There's a soft lump in the groin." These observations are common at newborn checkups. Both conditions go by the name "hernia," but they are not the same illness and they are not managed the same way. One typically resolves on its own; the other usually requires surgery. Mixing up the two leads to either unnecessary anxiety or a missed sense of urgency.

Understanding the difference is the kind of knowledge that helps a parent sit calmly in the examination room.

Umbilical Hernia — Most "Outies" Close on Their Own

An umbilical hernia occurs when the umbilical ring — the opening in the abdominal wall through which the umbilical cord passes — does not close completely after birth. It is seen in 10–20% of newborns [1] and is reported to be more common in premature infants [2]. When the baby cries or strains, the navel protrudes visibly. The bulge is soft and can be easily pushed back into the abdomen.

Spontaneous resolution is the norm: without any treatment, about 80% are reported to close by age one and about 90% by age two [1]. Hernias whose ring exceeds 2 cm in diameter, however, are less likely to close on their own [3]. A systematic review concluded that watching an asymptomatic umbilical hernia until age 4–5, regardless of its size, is safe and is standard practice at many pediatric hospitals; surgical repair (umbilicoplasty) is generally considered if it persists beyond that age [4].

Adhesive strapping — including the traditional practice of "coin taping," pressing a coin over the navel with tape — fell out of favor but has recently been taken up again as a common practice in Japan [1]. In a 2023 meta-analysis, however, strapping did not improve the overall closure rate compared with observation alone. It may speed closure (a difference was seen at 6 months of age) and help prevent a protruding navel from redundant skin, but the studies were highly heterogeneous, and reported complication rates — mostly skin trouble — ranged from 1.1% to 41.2% [1]. There is no need to tape a coin on at home; whether to try strapping is a decision to make with your child's doctor, keeping an eye on the skin.

Incarceration — the bowel becoming trapped in the hernia and unable to return — is extremely rare with umbilical hernias [2] (one estimate puts it at about 1 in 1,500 [3]). If the bulge suddenly becomes firm and the baby cannot be consoled, that warrants a medical visit.

Inguinal Hernia — Why Surgery Is the Expected Treatment

An inguinal hernia occurs when the processus vaginalis — a channel of peritoneum in the groin — fails to close after birth. In a Taiwanese nationwide cohort, about 4% of children had undergone hernia repair by age six; boys outnumbered girls roughly 4 to 1, and preterm birth was associated with a higher rate [5]. A soft lump appears in the groin when the baby cries or stands, and typically retreats when the baby is at rest.

Unlike umbilical hernias, inguinal hernias are not expected to resolve spontaneously. Surgery is the standard treatment. More importantly, the risk of incarceration is significant: bowel — and occasionally, in girls, the ovary — can become trapped in the inguinal canal, cutting off blood supply. This is a surgical emergency. In a systematic review of children awaiting elective repair, incarceration occurred in about 7% overall and about 11% of preterm children [6]. A Canadian study of children under two found that being younger than one year roughly doubled the risk, and that waiting more than 14 days after diagnosis was associated with about twice the risk of incarceration [7]. This is why a newly diagnosed inguinal hernia should not wait long before pediatric surgical evaluation.

The signs of incarceration are clear: the baby cries suddenly and inconsolably, and the lump in the groin becomes firm and does not reduce. Vomiting accompanying this picture increases urgency further.

Surgical repair (herniotomy) ligates the processus vaginalis through the groin; laparoscopic approaches are now also common. Complications after elective repair are uncommon — in a systematic review, recurrence and testicular atrophy each occurred in about 1% [6].

A Note for Boys — Check for Undescended Testicle at the Same Time

In boys with an inguinal hernia, there is a possibility of an associated undescended testicle (cryptorchidism) — the testicle not having descended into the scrotum. Because undescended testicle carries long-term implications for fertility and cancer risk, the position of the testicle should be checked whenever an inguinal hernia is identified in a boy. The American Urological Association guideline recommends referral to a specialist (pediatric urology or pediatric surgery) if the testicle has not descended into the scrotum by 6 months of age (corrected for prematurity) [8].

Translating Evidence into Everyday Decisions

• Umbilical hernia ("outie"): Watchful waiting is the default. There is no need to push it back manually or tape coins over it on your own. A hernia that persists beyond age 4–5, or a large diameter, is the usual reason to consult a pediatrician or pediatric surgeon
• Inguinal hernia: Once diagnosed, confirm with your physician whether a referral to pediatric surgery is appropriate — in most cases, it will be. Incarceration (sudden firmness and inconsolable crying) is a surgical emergency
• Boys with inguinal hernia: Ask about the testicular position at the same visit

Recording the size of an umbilical hernia over time, or noting when and how often an inguinal hernia bulge appears, provides useful context for surgical decision-making and for any future visits.

Summary

Despite their superficial similarity, umbilical and inguinal hernias have different natural histories and different levels of urgency. Umbilical hernias resolve on their own in the great majority of cases — there is no reason to panic. Inguinal hernias carry a real incarceration risk and warrant timely surgical assessment. Knowing which is which prevents both unnecessary worry and a dangerous delay.

References

1. Sugimoto T, Tahara K, Uchida K, Yoshimoto K. Efficacy of adhesive strapping on umbilical hernia in children: a systematic review and meta-analysis of cohort studies. World J Pediatr Surg. 2023;6(4):e000633. doi:10.1136/wjps-2023-000633. PMID: 37860276.
2. Ireland A, Gollow I, Gera P. Low risk, but not no risk, of umbilical hernia complications requiring acute surgery in childhood. J Paediatr Child Health. 2014;50(4):291–293. doi:10.1111/jpc.12480. PMID: 24372946.
3. Papagrigoriadis S, Browse DJ, Howard ER. Incarceration of umbilical hernias in children: a rare but important complication. Pediatr Surg Int. 1998;14(3):231–232. doi:10.1007/s003830050497. PMID: 9880759.
4. Zens T, Nichol PF, Cartmill R, Kohler JE. Management of asymptomatic pediatric umbilical hernias: a systematic review. J Pediatr Surg. 2017;52(11):1723–1731. doi:10.1016/j.jpedsurg.2017.07.016. PMID: 28778691.
5. Pan ML, Chang WP, Lee HC, et al. A longitudinal cohort study of incidence rates of inguinal hernia repair in 0- to 6-year-old children. J Pediatr Surg. 2013;48(11):2327–2331. doi:10.1016/j.jpedsurg.2013.06.004. PMID: 24210207.
6. Olesen CS, Mortensen LQ, Öberg S, Rosenberg J. Risk of incarceration in children with inguinal hernia: a systematic review. Hernia. 2019;23(2):245–254. doi:10.1007/s10029-019-01877-0. PMID: 30637615.
7. Zamakhshary M, To T, Guan J, Langer JC. Risk of incarceration of inguinal hernia among infants and young children awaiting elective surgery. CMAJ. 2008;179(10):1001–1005. doi:10.1503/cmaj.070923. PMID: 18981440.
8. Kolon TF, Herndon CD, Baker LA, et al. Evaluation and treatment of cryptorchidism: AUA guideline. J Urol. 2014;192(2):337–345. doi:10.1016/j.juro.2014.05.005. PMID: 24857650.