A 2-hour-old term newborn delivered after 18 hours of labor with vacuum extraction presents with diffuse soft swelling over the scalp that crosses the midline and suture lines. The swelling is pitting in nature with mild bruising. The structure marked **A** in the diagram represents this clinical finding. Which of the following is the most likely diagnosis and expected clinical course?

Explanation

## Why Caput succedaneum; resolves spontaneously within days without intervention is right The structure marked **A** is caput succedaneum, which is a diffuse soft swelling of the presenting part of the scalp caused by prolonged labor and/or vacuum extraction. It represents serosanguinous fluid collection in the subcutaneous tissue above the periosteum. The key distinguishing feature is that it **crosses suture lines and the midline**, is pitting in nature, is **present at birth**, and resolves spontaneously within days without specific intervention. This is consistent with the clinical presentation in the stem: diffuse swelling crossing suture lines, present at 2 hours of life, after prolonged labor and vacuum extraction. Per Nelson 21e and Williams Obstetrics 26e, caput succedaneum is rarely consequential and requires only reassurance and observation. ## Why each distractor is wrong - **Cephalhematoma; requires aspiration and monitoring for hyperbilirubinemia over weeks**: Cephalhematoma is a subperiosteal collection of blood that is **localized to one cranial bone and does NOT cross suture lines** — the opposite of the clinical finding described. It also typically appears hours to days after birth (not immediately at 2 hours) and resolves over weeks to months, not days. While hyperbilirubinemia monitoring is important for cephalhematoma, this is not the diagnosis here. - **Subgaleal hemorrhage; requires urgent fluid resuscitation and ICU admission**: Subgaleal hemorrhage is a life-threatening emergency with fluctuant swelling that crosses suture lines and extends to the neck and forehead, often with signs of hypovolemic shock, anemia, and DIC. The clinical presentation here is benign soft pitting edema without systemic signs — inconsistent with subgaleal hemorrhage. - **Molding of cranial bones; requires serial imaging to detect associated fractures**: Molding is temporary overlapping of cranial bones from passage through the birth canal and is not pathologic. It does not present as a soft tissue swelling and resolves within days without sequelae. Serial imaging is not indicated for simple molding. **High-Yield:** Caput succedaneum = diffuse, soft, pitting, **crosses sutures**, present at birth, resolves in **days**; Cephalhematoma = localized, firm, **respects sutures**, appears hours-days after birth, resolves in **weeks-months**. [cite: Nelson Textbook of Pediatrics 21e; Williams Obstetrics 26e]