Individuals can be born with scars. This occurs due to unique processes of fetal development and wound healing within the womb, where injuries can heal differently than after birth, sometimes leading to scar formation.
The Science of Fetal Scarring
Fetal wound healing differs from adult wound healing, especially in early gestation. During the first and second trimesters, fetal skin wounds often heal without forming scars, regenerating tissue to its original state, including hair follicles and sebaceous glands. This scarless healing is attributed to several biological factors unique to the fetal environment.
The fetal wound environment exhibits a reduced inflammatory response compared to adult wounds, with fewer inflammatory cells like neutrophils and macrophages. Fetal fibroblasts, the cells responsible for synthesizing connective tissue, show different behaviors, producing more Type III collagen, which is finer and more rapidly deposited than the Type I collagen predominant in adult scars. The extracellular matrix in fetal wounds also has higher concentrations of hyaluronic acid, which is thought to promote scarless repair by influencing cell function and proliferation.
As gestation progresses, the ability of fetal skin to heal without scarring diminishes, transitioning to scar formation around 24 weeks. This change is linked to the maturation of the fetal immune system and changes in growth factor profiles, such as the balance of transforming growth factor-beta (TGF-β) isoforms. A higher ratio of TGF-β3 to TGF-β1 is associated with scarless healing, while an increase in TGF-β1 can promote scarring.
What Leads to Scars at Birth?
Several specific events or conditions occurring during pregnancy can result in a baby being born with scars. Surgical interventions performed on a fetus, known as fetal surgery, are a direct cause of scarring. Procedures like those for spina bifida or twin-to-twin transfusion syndrome require incisions that, despite the unique fetal healing capabilities, can leave marks.
Amniotic band syndrome is another cause, where thin, fibrous strands from the amniotic sac can entangle and constrict developing fetal body parts. This constriction can lead to injury, reduced blood flow, and subsequent scarring, or even congenital amputation of digits or limbs. The severity of the scar depends on the tightness and duration of the band’s constriction.
Intrauterine infections, such as those caused by varicella or herpes viruses, can also damage fetal skin and lead to scarring. Severe inflammatory responses within the womb, whether from infection or other conditions, can disrupt the normal healing process and result in permanent skin lesions. Trauma to the pregnant parent, though rare, could potentially injure the fetus and cause scarring. Certain rare genetic skin conditions, like aplasia cutis congenita, involve localized areas of missing skin at birth, which can lead to scar-like lesions.
Identifying Congenital Scars
Congenital scars can present with varied appearances, often differing from typical adult scars. These marks might be paler than the surrounding skin or, in some cases, hyperpigmented. Their texture can range from smooth and supple to depressed or atrophic, and they may lack hair follicles or sweat glands. The location and shape of congenital scars are diverse, depending on the underlying cause.
Distinguishing congenital scars from common birthmarks is important. Birthmarks, such as Mongolian spots, salmon patches, or port-wine stains, are often due to variations in blood vessels or pigment-producing cells, and have characteristic colors and textures that differ from scars. A port-wine stain, for example, is a flat, pink or purple vascular mark, while a scar often involves fibrous tissue changes.
If a newborn has any unusual or concerning skin marks, seeking evaluation from a healthcare professional, such as a pediatrician or dermatologist, is recommended. A medical professional can accurately diagnose the mark and provide guidance. This assessment ensures proper identification and rules out any associated health concerns.