KEY POINTS Compression during early morphogenesis (the first trimester) can result in three types of defects: molded deformations, incomplete morphogenesis, and disruptions of morphogenesis. Experimental animal studies showed that early amniotic sac puncture caused defects similar to Pierre Robin sequence, cleft palate, syndactyly, and limb-reduction defects. Limb-body wall complex is a rare defect characterized by extensive extremity and body wall defects, often associated with low birth…

KEY POINTS Ectopic pregnancy occurs when a fertilized ovum implants outside the uterus, most commonly in the fallopian tube. Risk factors for ectopic pregnancy include tubal damage, prior ectopic pregnancy, use of intrauterine devices, tubal sterilization, infertility, pelvic inflammatory disease, genital infections, multiple sexual partners, endometriosis, and cigarette smoking. Abdominal pregnancies have a higher maternal mortality rate compared with tubal pregnancies and intrauterine pregnancies due to…

KEY POINTS Fetal movement is crucial for normal joint development, and lack of movement can lead to joint contractures. Prenatal diagnosis of fetal akinesia may reveal additional structural abnormalities such as cystic hygroma, increased nuchal translucency, and hydrops fetalis. Fetal akinesia deformation sequence (FADS) is a term used to describe the causally heterogeneous conditions characterized by fetal akinesia and associated malformations. Experimental studies in animals have…

KEY POINTS Amniotic fluid tends to decrease during the last trimester of pregnancy, and a serious deficiency can result in fetal constraint. Oligohydramnios may be caused by renal/urinary tract malformations or amniotic rupture, accompanied by constrictive amnion strands, which can lead to various birth defects. Renal oligohydramnios is predominantly caused by congenital abnormalities of the kidney and urogenital tract. Oligohydramnios is associated with poor placental function,…

KEY POINTS Various types of uterine malformations, such as bicornuate or myomatous uterus, can lead to small uterine cavity deformation, increasing the risk of fetal deformation and complications. Diagnostic procedures like hysterosalpingography, laparoscopy, and 3D ultrasonography are more accurate in identifying congenital uterine anomalies compared with hysterosalpingography alone. Different types of uterine anomalies are associated with specific reproductive outcomes, including increased rates of miscarriage, preterm birth,…

KEY POINTS Factors contributing to face presentation include fetal anomalies, contracted pelvis, fetopelvic disproportion, or cord around the neck. Face presentation is more common in large infants (>4000 g), small infants (<2300 g), and cephalopelvic disproportion. Cesarean section is considered if the fetus is large, the mother has a relatively small pelvis, or there is a persistent mentum posterior presentation with arrested descent. Manual conversion from…

KEY POINTS Transverse lie is the second most common nonvertex presentation during delivery, occurring in 1.2–3 per 100 deliveries. Multiparity, prematurity, placenta previa, polyhydramnios, uterine anomalies, and uterine myomas are associated with transverse lie. Laxity of abdominal musculature in multiparous women is considered the primary factor contributing to transverse lie in these women. Transverse lie can lead to facial flattening, limited mandibular growth, retroflexed head, prominent…

KEY POINTS Breech presentation is considered normal in premature fetuses before 32 weeks of gestation but is responsible for one-third of all deformations in term newborns. Factors leading to breech presentation include prematurity, twinning, chronic amniotic fluid leakage, uterine malformations, placenta previa, maternal hypertension, and fetal malformations. Primigravida women, especially older primigravida women, are more likely to have breech presentation due to uterine shape and limited…

KEY POINTS Wormian bones are accessory bones found within cranial suture lines that vary in size and quantity, with few and small bones being common and many large bones being extremely rare. A majority of children with an excessive number of Wormian bones have some abnormality of the central nervous system. They occur most commonly in the lambdoid sutures and within fontanels. Wormian bones are thought…

KEY POINTS Cephalohematoma is a subperiosteal extracranial hemorrhage often from an injury to the cranial periosteum during labor or a traumatic delivery. Risk factors include vacuum extraction, forceps delivery, fetal scalp monitors, instrumentation, and increased birth weight. Complications of cephalohematoma can include underlying skull fracture, anemia, hyperbilirubinemia, calcification, or infection. Cephalohematomas are usually localized and may resolve spontaneously within a few weeks or months. In rare…

KEY POINTS Aplasia cutis congenita (ACC) is a congenital absence of skin, most commonly affecting the scalp and characterized by raw areas that mature into atrophic scars devoid of hair. ACC can occur in isolation or associated with other abnormalities and malformations, such as spinal dysraphism, encephaloceles, epidermal nevus, or nevus sebaceous syndrome. The cause of ACC is heterogeneous and can include vascular disruption, infection, trauma,…

KEY POINTS Parietal foramina are symmetric oval calvarial defects located near the parietal eminences, separated by a narrow bridge of bone. Diagnosis is aided by palpation, radiography, antenatal sonography, and magnetic resonance imaging. Parietal foramina can occur in isolation or as part of multiple congenital anomaly syndromes with autosomal dominant inheritance with variable expression and intrafamilial variability observed. Parietal foramina can manifest as cranium bifidum in…

KEY POINTS The anterior fontanel on rare occasions ossifies and forms a bony plate. An anterior frontal bone can be seen in normal infants as a variant or in association with craniosynostosis. The anterior fontanelle is an integral part of the pediatric exam, and any abnormalities such as delayed closure can be associated with various pathologic conditions. Diagnosis is important to differentiate it from craniosynostosis or…

KEY POINTS Vertex craniotabes is characterized by diminished mineralization in the superior portions of the parietal bones, caused by prolonged forceful pressure on vertex during birth. The affected region of the calvarium feels soft to palpation and may exhibit a “ping-pong” sensation on compression. The sides of the calvarium and other skeletal regions are typically unaffected, helping to differentiate it from generalized mineralization problems. The condition…

KEY POINTS Vertex birth molding is the bony adjustments within the cranial vault and soft tissue swelling due to external fetal head compression during delivery. Factors such as fetal head position and size, gestational age, maternal pelvic shape, and uterine contractions influence the degree of molding. During vertex molding, the frontal and occipital bones slide under the parietal bones, elongating the occipitofrontal diameter and reducing the…

KEY POINTS Multiple sutural synostosis can result from a profound degree of prenatal head constraint or genetic mutations in genes associated with a syndromic form of craniosynostosis. Differential diagnosis is important considering the natural history and prognosis of different syndromes. Elevated intracranial pressure is more common in multiple sutural synostosis compared to single suture synostosis. Symptoms include a cloverleaf-shaped head, increased intracranial pressure signs, optic atrophy,…

KEY POINTS Lambdoidal craniosynostosis is often an isolated anomaly but can be associated with muscular torticollis or an abnormal fetal lie/birth presentation. Differential diagnosis includes nonsynostotic deformational posterior plagiocephaly, synostotic anterior plagiocephaly, and other forms of craniosynostosis. Unilateral lambdoidal craniosynostosis results in the protrusion of the ipsilateral mastoid bone, palpable sutural ridging, occipital flattening, downward displacement of the auricle, and trapezoidal cranial asymmetry. Early recognition and…

KEY POINTS The metopic suture is the first cranial suture to close and normally closes by 8 to 9 months. Mild degrees of metopic ridging occur frequently at birth, but unless there is progressive distortion of the orbits, it usually resolves. Metopic synostosis is characterized by trigonocephaly, lateral supraorbital retrusion, and hypotelorism. Trigonocephaly can occur as an isolated anomaly or as part of a syndrome or…

KEY POINTS Coronal craniosynostosis may occur as an isolated finding or as part of several genetic disorders. Coronal craniosynostosis can be unilateral or bilateral and can be caused by early descent of the fetal head into a constraining position, or aberrant fetal lie, or constraint within a bicornuate uterus. Late gestational constraint may cause an appearance similar to coronal synostosis at birth, but spontaneous restitution occurs…

KEY POINTS Sagittal craniosynostosis limits lateral cranial expansion, with progressive frontal and/or occipital prominence and ridging along the mid-posterior portion of the skull. Sagittal synostosis can result from fetal head constraint secondary to factors such as twining, oligohydramnios, or early descent of the fetal head into the maternal pelvis with fetal head entrapment, resulting in biparietal constraint. Various surgical techniques have been used to correct sagittal…