Braxton Hicks contractions are physiological contractions of myometrium that occur in pregnancy. They are often sporadic and start by ~6 weeks.
It may be seen as a transient change myometrial thickness 2.
History and etymology
Named after John Brax...
A Breus mole is a term that was given to a very large subchorionic hemorrhage, an unfortunate misnomer because this entity bears no relationship to the molar pregnancy.
The lesions are a mass of fibrin formed secondary to thrombosis. They dissect and form a subchorionic thrombohemato...
The broad ligament is the lateral folds of the parietal peritoneum which reflect over the upper genital tract in females.
The broad ligament extends from the lateral aspect of the uterus to the lateral pelvic wall and can be divided into three main components - the mesosalpinx, m...
Bunch of grapes sign refers to the imaging appearance of multiple cystic spaces or lesions and it has been described for multiple pathologies:
bunch of grapes sign (hydatidiform mole) 7
bunch of grapes sign (bronchiectasis) 3
bunch of grapes sign (IPMN) 6
bunch of grapes sign (botryoid rhabd...
The butterfly sign refers to the normal appearance of the choroid plexuses on axial imaging of the fetal brain, commonly observed on the antenatal ultrasound. Its absence may suggest holoprosencephaly 1.
In the CNS, the term should not be confused with a butterfly glioma, which is a glioblastom...
Cesarean scar ectopic pregnancy (CSEP) is a rare type of abnormal implantation. It is often considered the rarest type of ectopic pregnancy, although some do not include it in this category as implantation occurs within the uterus.
It has an estimated incidence of ~1:1800-2200 pre...
Cesarean section (also known as C-section, CS and C/S) is the most frequently done major abdominal surgery in females 1.
Many forms of Cesarean section have been described, but the most popular variation is the low transverse approach following a Pfannenstiel or Joel-Cohen ...
A calcified yolk sac has been described as a sign of intrauterine demise. The cause of yolk sac calcification in failed pregnancies is uncertain but is likely related to dystrophic calcification.
abnormal increased echogenicity of the yolk sac with posterior a...
Camptodactyly arthropathy coxa vara pericarditis (CACP) syndrome is a rare condition principally characterized by
congenital or early-onset camptodactyly and childhood-onset non-inflammatory arthropathy
coxa vara deformity or other dysplasia associated with progressive hip disease
Cardiac rhabdomyomas are a type of benign myocardial tumor and are considered the most common fetal cardiac tumor. They have a strong association with tuberous sclerosis.
Cardiac rhabdomyomas are often multiple and can represent up to 90% of cardiac tumors in the pediatric populat...
Carpenter syndrome, also called acrocephalopolysyndactyly type II (ACPS type II) is an extremely rare autosomal recessive congenital disorder.
It is characterized by a number of features which include:
A helpful mnemonic for remembering some causes of oligohydramnios is:
R: renal abnormalities (decreased urine output)
P: premature rupture of membranes
C: chromosomal anomalies
Cebocephaly refers to a type of rare midline craniofacial anomaly where there is a single nostril (which usually ends blindly 6-7) with proboscis-like nose 8 and hypotelorism.
holoprosencephaly: particularly alobar holoprosencephaly
Cenani-Lenz syndactyly (CLS) is a very syndrome primarily characterized by:
syndactyly/oligodactly: syndactyly is often complete and gives a spoon hand type appearance
It carries an autosomal recessive inheritance.
It was first described...
The cephalic index (CI) is a value calculated using two fetal biometric parameters which are the occipitofrontal diameter (OFD) and the biparietal diameter (BPD).
It is calculated as:
cephalic index (CI) = biparietal diameter (BPD)/occipitofrontal diameter (OFD) x 100
The cephalic index gi...
Cephalocele refers to the outward herniation of CNS contents through a defect in the cranium. The vast majority are midline.
The estimated incidence is 0.8-4:10,000 live births 13 with a well recognized geographical variation between types; however, this has been speculated to be ...
Cephalohematomas are traumatic subperiosteal hematomas of the skull that are usually caused by birth injury. They are bound between the periosteum and cranium, and therefore cannot cross sutures. Being bound by a suture line distinguishes them from subgaleal hematoma, which can cross sutures.
Cephalopagus twins are a rare type of conjoined twins. They are fused from the vertex to the umbilicus. They share a common cranium with either one composite face or two faces on opposite sides of the conjoined head.
The thoraces are fused with fusion of liver, heart, and the upper gastrointest...
Cephalopelvic disproportion (CPD) occurs when there is a mismatch between the size of the fetal head and the maternal pelvis causing a difficulty in the safe passage of the fetus through the birth canal.
Cephalopelvic disproportion may be caused by the fetal head outgrowing the capac...
Cerebellar clefts are rare congenital abnormalities of the posterior fossa, where cerebellar grey matter extends from the surface into the parenchyma, in some cases even reaching the fourth ventricle.
Language and speech disorders, cognitive impairment, truncal ataxia, o...
Cerebroplacental ratio (CPR) is an obstetric ultrasound tool used as a predictor of adverse pregnancy outcome in both small for gestational age (SGA) and appropriate for gestational age (AGA) fetuses. An abnormal CPR reflects redistribution of cardiac output to the cerebral circulation, and has ...
Staging of cervical cancer can either be based on the TNM or FIGO system.
Revised FIGO staging of cervical carcinoma 2018 8
FIGO no longer includes Stage 0 (Tis)
I: confined to cervix uteri (extension to the corpus should be disregarded)
IA: invasive carcinoma only diagnosed by microscopy
Cervical ectopic pregnancy is a rare subtype of ectopic pregnancy, in which a gestational sac is seen at the endocervical canal below the closed internal os.
It accounts for ~0.15-1% of all ectopic pregnancies.
Implantation of the fertilized ovum occurs within the cer...
Cervical incompetence refers to a painless spontaneous dilatation of the cervix and is a common cause of second trimester pregnancy failure.
The estimated incidence varies geographically and generally thought to be around 1-1.5% of all pregnancies 1,15.
Sequential morphological ultrasound changes of the endocervical canal with cervical incompetence can be remembered using the mnemonic:
Trust Your Vaginal Ultrasound
T-shaped (normal internal cervical os)
In obstetric and gynecological imaging, the cervical length is defined as the distance between the internal cervical os and the external cervical os.
the cervical length is most accurately assessed on a transvaginal scan with an empty bladder
in a normal gr...
The term cervical stenosis can refer to:
stenosis of the uterine cervix
bony cervical canal stenosis (cervical spinal stenosis)
The cervix or uterine cervix is the lower constricted segment of the uterus providing the passage between the uterus proper and the vagina.
The cervix is somewhat conical in shape, with its truncated apex directed posteriorly and inferiorly. The inferior aspect of the cervix pro...
The term Cesarean scar niche (defect) refers to the presence of a hypoechoic area within the myometrium in the isthmus (lower uterine segment) with discontinuation of myometrium at the site of previous Cesarean section scar. A niche has been described as the indentation of myometrium of around 1...
Chiari III malformation is an extremely rare anomaly characterized by a low occipital and high cervical encephalocele with herniation of posterior fossa contents, that is, the cerebellum and/or the brainstem, occipital lobe, and fourth ventricle.
agenesis of the corpus...
Chiari II malformations are relatively common congenital malformation of the spine and posterior fossa characterized by myelomeningocele (lumbosacral spina bifida aperta) and a small posterior fossa with descent of the brainstem and cerebellar tonsils and vermis. Numerous associated abnormalitie...
CHILD (congenital hemidysplasia with ichthyosiform erythroderma and limb defects) syndrome comprises:
Ch: congenital hemidysplasia
I: ichthyosiform erythroderma
develops at or shortly after birth
unilateral erythema and scaling, with a distinct demarcation in the middle of the trunk 2
Chondrodysplasia punctata (CDP) is a collective name for a heterogenous group of skeletal dysplasias. Calcific stippling of cartilage and peri-articular soft tissues is often a common feature.
It can be broadly divided into rhizomelic and non-rhizomelic forms:
Chondroectodermal dysplasia, also known as the Ellis-van Creveld syndrome, is a rare type of skeletal dysplasia. It is classified as a type of mesomelic limb shortening 5.
Clinical features include:
narrowing of thorax with short ribs
small and flared ilia
Chorioamnionitis refers to infection of the chorion and amnion during pregnancy.
Chorioamnionitis affects an estimated 2-4% of term deliveries and 40-70% of preterm deliveries1.
Clinically, chorionamnionitis can present with the following maternal signs and...
Chorioamniotic separation (CAS) is an intra-uterine event which can occur in pregnancy and is characterized by separation of placental (chorion) and fetal (amnion) membranes.
The membranes are separated in early gestation, accounting for the appearance of the amniotic sac. After appr...
Choriocarcinoma is an aggressive, highly vascular tumor. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-g...
The staging system for choriocarcinoma (usually refers to uterine choriocarcinoma) is the FIGO staging system and is as follows 1:
stage I: disease limited to the uterus
stage II: disease out of the uterus but limited to the female genital tract
stage III: metastasis in the lung with or with...
The chorion is one of the embryonic membranous structures that enclose both the fetus as well as the amnion. The chorion begins to form chorionic villi towards its outer surface, which initially serves to provide nutrition to the developing embryo.
Part of the chorionic villi arborize more ext...
Chorionic bump is a finding that can be uncommonly seen in a first-trimester scan. It may represent a small hematoma bulging into the gestational sac or an anembryonic (failed) second pregnancy that is being resorbed. It is also seen in some patients undergoing infertility treatment.
The chorionic plate is a synonym for the fetal side of the placenta. The maternal side of the placenta is termed the basal plate.
Some pathologies and processes are localized to the chorionic plate, and evaluation of the chorionic plate is a part of placental grading.
Chorionic villus sampling (CVS) is an antenatal procedure for prenatal diagnosis of chromosomal or genetic disorders in the fetus. It entails getting a sample of the chorionic villus (placental tissue) and testing it.
A transabdominal or transcervical approach is selected depending on the posit...
Antenatal choroid plexus cysts are benign and are often transient typically resulting in utero from an infolding of the neuroepithelium.
They should not be confused with adult choroid plexus cysts (which are very commonly found at autopsy and likely degenerative), large intraventricular simpl...
There are a large number of recognized chromosomal anomalies (many with eponyms). When there is a change in the absolute number of chromosomes these are subgrouped as aneuploidic anomalies.
They can cause a variable degree of disability with outcomes ranging from no effect (in some balanced tra...
Circummarginate placenta is an uncommon variation in placental morphology. The chorionic membranes insert inward from the margin of placental edge, similar to circumvallate placenta, but unlike circumvallate placenta, the placental edge is not thickened and rolled up, and there is no central dep...
Circumvallate placenta refers to a variation in placental morphology in which, as a result of a small chorionic plate, the amnion and chorion fetal membranes ‘double back’ around the edge of the placenta.
The prevalence is estimated to be around 1-7% 3.
There is an inw...
Cleft lip and palate is one of the commonest of neonatal facial anomalies. In ~80% of cases, the two features tend to occur together 6.
It is estimated to occur with an incidence of ~1 in 700-to-1000 live births 1. This can increase to 4% for a sibling of a previously affected fet...
Clinodactyly is a descriptive term that refers to a radial angulation at an interphalangeal joint in the radio-ulnar or palmar planes. It typically affects the 5th finger.
The estimated incidence is highly variable dependent on sampling and has been reported to range between 1-18...
Cloacal exstrophy (CE) is an extensive congenital abdominal wall defect which encompasses:
exstrophy of the bladder
lower abdominal wall defect
The estimated prevalence is at around 1 in 50,000 to 200,000 live births. There is a recognized male predilection with a M...
Cloverleaf skull, also known as kleeblattschädel syndrome or deformity, refers to a type of severe craniosynostosis which gives the skull a cloverleaf shape. It is very rare, with less than 130 case reports globally. It typically results from intrauterine premature closure of the sagittal, coron...
There are several described cockade signs in radiology:
cockade sign (intraosseous lipoma)
cockade sign (aorto-left ventricular tunnel) 1
cockade sign (appendicitis) 2
cockade sign (hypertrophic pyloric stenosis) 3
cockade sign (GI tumors) 4
Coexistent molar pregnancy refers to an extremely rare situation where there is a molar pregnancy occurring simultaneously with normal intra-uterine pregnancy.
The estimated incidence is at ~1:10,000-100,000 gestations (for a complete hydatidiform mole and a normal pregnancy) 2.
Coffin-Lowry syndrome (CLS) is a rare X-linked genetic syndrome affecting multiple body parts.
The condition tends to affect males much more due to its X-linked inheritance. The estimated incidence is at around 1:40,000-50,000.
It is characterized by a numb...
A complete hydatidiform mole (CHM) is a type of molar pregnancy and falls at the benign end of the spectrum of gestational trophoblastic disease.
A complete hydatidiform mole is the commonest type of gestational trophoblastic disease.
Complete moles are characterized ...
Complete hydatidiform mole with coexistent fetus (CHMCF) is an extremely rare entity whereas the name suggests there is a twin pregnancy with a complete hydatidiform mole and a normal fetus.
It is seen extremely rarely, with an estimated incidence of one in 22,000–100,000 pregnan...
A complete miscarriage is defined as a cessation of vaginal bleeding with no evidence of retained products of conception or a gestation sac in a woman who previously had an ultrasound confirmed intrauterine pregnancy.
Shows an empty uterus with no fetal compon...
A complete placenta previa, also known as a type IV placenta previa, is the most severe in terms of the placenta previa spectrum. It is also the least likely to resolve with advancing gestation if detected in early pregnancy 1,3.
In this situation, the placenta entirely covers the in...
Congenital cervical teratoma refers to a teratoma arising in the cervical region. They are thought to account for ~3% of teratomas in childhood/infancy 3.
The estimated occurrence in neonates is ~1:20,000-40,000 live births 8.
Most tumors are diagnosed at b...
Congenital cytomegalovirus infections result from intrauterine fetal infection by cytomegalovirus (CMV).
Cytomegalovirus is the most common cause of intrauterine infection and the most common cause of congenital infective and brain damage, occurring in 0.2-2.4% of live births.
Congenital goiter is a rare cause of neck swelling in neonates and is demonstrated as diffuse/nodular thyroid gland enlargement.
It is a common endocrine disease in newborns and affects approximately 1:2000-4000 live births.
There may be a difficult vaginal...
A congenital granular cell myoblastoma (also known as congenital epulis) is a very rare benign tumor which classically presents in the fetal-neonatal population.
It occurs almost exclusively in females when it presents in the fetal-neonatal population although no such predilection...
Congenital high airway obstruction syndrome or sequence (CHAOS) refers to a rare, often lethal, congenital laryngotracheal condition and is primarily characterized by obstruction to the fetal upper airway.
CHAOS can be of three possible types 2:
complete laryngeal atresia without an...
Congenital hypothyroidism (CHT), previously known as cretinism, can be of thyroidal or central (hypothalamic/pituitary) origin and can have a widely diverse molecular etiology.
Most children are asymptomatic at birth and are diagnosed after screening. In untreated congeni...
The group of the most common congenital infections are referred to by the mnemonic TORCH or STORCH. They usually cause mild maternal morbidity but are related to serious fetal consequences 4.
In cases where no serological, microbiological or immunological evidence of infection can be identified...
Congenital limb amputation is the absence of a fetal limb or part of a limb that usually occurs due to disruption of vascular supply.
Congenital amputations occur in 0.5 (range 0.03-1) per 1000 live births 2.
They are slightly more common in the upper limb (60%) than ...
A congenital (primary) megaureter encompasses causes of an enlarged ureter which are intrinsic to the ureter, rather than as a result of a more distal abnormality; e.g. bladder, urethra (see secondary megaureter). It includes:
obstructed primary megaureter
refluxing primary megaureter
Congenital pulmonary airway malformations (CPAM) are multicystic masses of segmental lung tissue with abnormal bronchial proliferation. CPAMs are considered part of the spectrum of bronchopulmonary foregut malformations.
Until recently they were described as congenital cystic adeno...
Congenital renal anomalies comprise of vast spectrum of pathologies and include:
congenital renal hypoplasia
congenital cystic renal disease
infantile polycystic renal disease: autosomal recessive polycystic kidney disease (ARPKD):...
Congenital rubella syndrome is a spectrum of congenital abnormalities that result from primary maternal infection with the rubella virus. It falls under the TORCH group of infections.
It is important to note that reinfection/reactivation of maternal infection has a significantly lower risk of f...
Congenital talipes equinovarus is considered the most common anomaly affecting the feet diagnosed on antenatal ultrasound.
While some use talipes equinovarus and clubfoot synonymously, in certain publications, the term clubfoot is considered a more general descriptive term that des...
There are many classification systems for congenital utero-vaginal anomalies. These include:
Buttram and Gibbons classification 2
American Fertility Society (AFS) classification
Modified Rock and Adam - AFS classification
Modified Rock and Adam - AFS classification
This classification divid...
Congenital hallux valgus is a very rare finding wherein a fetus or newborn shows lateral deviation of the first toe(s). When found on prenatal imaging, bilateral congenital/foetal hallux valgus is highly suggestive of fibrodysplasia ossificans progressiva 1,2.
Conjoined twin pregnancy is a rare occurrence resulting from the failure of a zygote to separate completely after 13 days 11. This results in the twins being physically joined.
The prevalence of conjoined twins ranges from 1:50,000 to 1:200,000. They are more common in parts of So...
Conotruncal heart defects are a group of congenital cardiovascular anomalies. They are a leading cause of symptomatic cyanotic cardiac disease diagnosed in utero.
They may account for up to a fifth of all congenital cardiac anomalies diagnosed prenatally 2.
Cordocentesis is a method of fetal blood sampling which is usually carried out under ultrasound guidance.
It may be performed for various reasons which include:
establish the degree of a fetal anemia
further investigation of an underlying chromosomal anomaly
A cord presentation (also known as a funic presentation) is a variation in the fetal presentation where the umbilical cord points towards the internal cervical os or lower uterine segment. It may be a transient phenomenon and usually considered insignificant until ~32 weeks. It is concerning if...
Cornelia de Lange syndrome (CdLS) is an extremely rare clinically heterogeneous developmental disorder of unknown etiology. Although the described clinical symptomatology is very broad, the majority of cases include growth impairment, learning disability and dysmorphic facies.
Ruptured corpus luteal cysts are one of the commonest causes of spontaneous hemoperitoneum in a woman of reproductive age.
Presentation is variable, ranging from completely asymptomatic to severe abdominal pain due to peritoneal irritation.
The corpus luteum i...
The corpus luteum (plural: corpora lutea) is a temporary endocrine structure involved in ovulation and early pregnancy.
During ovulation, the primary follicle forms the secondary follicle and subsequently the mature vesicular follicle.
At ovulation the follicle ruptures expelling the ovum into...
Craniopagus twins are conjoined twins that are fused at any part of the skull, except the face, foramen magnum, skull base and the vertebral column.
The fused structures are most often the cranium, meninges, and dural venous sinuses. Brains tend to be separate; however, they may be connected by...
Craniorachischisis, also known as craniorachischisis totalis, is a rare birth defect and the most severe of the neural tube defects. It refers to the presence of both anencephaly and spina bifida.
In one study the prevalence of craniorachischisis was 0.51 per 10,000 live births in...
Crouzon syndrome is rare disorder characterized by premature craniosynostoses.
abnormal calvarial shape: in severe case can give a "cloverleaf skull"
shallow orbits with exophthalmos
mid facial hypoplasia
It carries an autosomal dominant...
Crown rump length (CRL) is the length of the embryo or fetus from the top of its head to bottom of torso. It is the most accurate estimation of gestational age in early pregnancy, because there is little biological variability at that time.
CRL is measured as the largest dimension ...
The Currarino syndrome is a complex condition variably comprised of characteristic congenital anomalies of the sacrum, anorectum and presacral soft tissues. It is also known as the Currarino triad or ASP triad, however, not all three features are always present 6.
anorectal malformation or con...
Cyclopia refers to a rare fetal malformation characterized by a single palpebral fissure and a single midline orbit. This orbit may contain either a single globe or two separate globe.
The condition is thought to affect approximately 1 in 40,000 to 95,000 births (inclusive of stil...
Cystic hygroma, also known as cystic or nuchal lymphangioma, refers to the congenital macrocystic lymphatic malformations that most commonly occur in the cervicofacial regions, particularly at the posterior cervical triangle in infants.
While these lesions are commonly known as cys...
Cystic hygroma and occipital meningocele are both differential diagnosis for an antenatally detected cystic collection noted on the posterior aspect of the head and neck.
A simple differentiation can be made based on the contents and presence of septations:
cystic hygroma will present as a wel...
Cystic renal dysplasia refers to a subgroup of congenital anomalies of the kidney and urinary tract characterized by the dysplastic renal parenchyma and formation of cysts. The most severe form is multicystic dysplastic kidney, in which functional renal parenchyma is absent and only undifferenti...
Dandy-Walker variant (DWv) is a less severe posterior fossa anomaly than the classic Dandy-Walker malformation (DWM) and is considered being on the lesser end of the disease spectrum in the Dandy-Walker continuum.
This term was created to include those malformations that do not mee...
Decidual cast refers to the presence of an amount of relatively echogenic material in the uterine cavity in the context of an ectopic pregnancy.
A decidual reaction is feature seen in very early pregnancy where there is a thickening of the endometrium around the gestational sac. A thin decidual reaction of less than 2 mm is considered one of the features suggestive of an anembryonic pregnancy 2. A decidual reaction in some situations can...
The deepest (maximal) vertical pocket (DVP) depth is considered a reliable method for assessing amniotic fluid volume on ultrasound 1,2. It is performed by assessing a pocket of a maximal depth of amniotic fluid which is free of an umbilical cord and fetal parts.
The usually accepted values are...
Demise of a twin is a complication that can occur in a twin pregnancy (particularly monochorionic pregnancies) and may be due to a wide range of conditions. Once the twin dies, most of the dead twin tends to be absorbed leaving behind a small flattened remnant known as the fetus papyraceus.