Can Aplasia Cutis Congenita Be Seen on Ultrasound?

No, aplasia cutis congenita (ACC) is almost never detected on a standard prenatal ultrasound. It is completely normal for parents to feel confused or frustrated when this missing skin is discovered at birth, but missing it on an ultrasound does not mean your medical team made a mistake. Because ACC is primarily a surface-level skin defect, it simply cannot be seen with routine prenatal imaging ^[1][2].

What Routine Ultrasounds Look For

Routine pregnancy ultrasounds are highly effective medical tools, but they have specific limitations. They are designed to monitor the baby’s overall growth, evaluate major internal organs (like the brain, heart, and kidneys), check bone development, and measure amniotic fluid levels ^[3]. They are not designed to examine the surface of the skin ^[1]. (Note: Similarly, standard maternal blood screening tests are designed to look for specific chromosomal or neural tube issues, not localized skin defects, which is why they also do not detect ACC).

Why the Skin is Hard to See on Ultrasound

There are several scientific and technical reasons why an ACC lesion does not show up on a prenatal sonogram:

• Lack of tissue contrast: Ultrasound machines create images based on how sound waves bounce off different tissues. Dense structures like bone reflect sound waves well, creating clear, bright images. Skin is very thin, and a missing patch of skin does not create enough contrast to be visible on a standard scan ^[1][2].
• Bright bone reflections: The most common location for ACC is the baby’s scalp ^[4]. Because the bones of the fetal skull are very dense, they reflect ultrasound waves so powerfully that the bright image of the skull completely washes out the thin, delicate layer of skin resting just above it ^[5].
• Fetal positioning: Late in pregnancy, the baby’s head is often positioned deep in the mother’s pelvis, making it difficult to get a clear view of the top of the scalp ^[5].

As a result, ACC is considered a clinical diagnosis — meaning it is identified by a doctor physically looking at the skin after the baby is born ^[1][4].

When Might Something Be Suspected?

While the missing skin itself is rarely seen, signs of other conditions associated with ACC might occasionally be picked up on an ultrasound. ACC can sometimes occur alongside deeper structural issues or genetic syndromes ^[6][7].

It is important to know that most cases of ACC are isolated, meaning the baby is otherwise completely healthy ^[6]. However, if a baby has a condition like Adams-Oliver syndrome or Trisomy 13, doctors might detect heart defects, limb differences (like missing fingers or toes), or severe skull bone defects during prenatal visits ^[3][8]. If your baby’s prenatal ultrasounds were otherwise normal, it is highly likely that they do not have these severe, systemic syndromes.

In rare cases where an ACC lesion is very large and involves missing skull bone (a calvarial defect) or exposed underlying tissues, advanced 3D ultrasound, volume contrast imaging, or a fetal MRI might detect the bone defect or fluid collections ^[5][8]. However, even in these more complex cases, the specific diagnosis of aplasia cutis congenita is usually only confirmed after delivery ^[1][2].

Moving Forward After Birth

Finding out about ACC at delivery is almost always a surprise ^[2]. Once the baby is born, the medical team’s immediate focus will shift from prenatal imaging to carefully evaluating the lesion, checking for any underlying bone involvement, and ensuring proper wound care ^[6][2].

To check the bone and tissue underneath the skin, doctors will do a physical exam and may order a simple postnatal ultrasound or MRI of the baby’s head ^[6][2]. Fortunately, many isolated cases of ACC are small and heal very well with basic conservative care, which often just involves gentle cleansing and applying prescribed healing ointments ^[9][10].