108 results
Article
Amnion
Amnion refers to a membranous structure which covers and protects the embryo. It forms inside the chorion. The amnion usually fuses with the outer chorion by around 14 weeks of gestation.
Radiographic features
Ultrasound
The amnion can be visualized in most pregnancies before the 12th week of...
Article
Posterior urethral valves
Posterior urethral valves (PUV), also referred to as congenital obstructing posterior urethral membranes (COPUM), are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy.
Epidemiology
Posterior urethral valves are congenital and on...
Article
Monochorionic diamniotic twin pregnancy
A monochorionic diamniotic (MCDA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac but have two amniotic sacs and two yolk sacs.
Epidemiology
It accounts for the vast majority (70-75%) of monozygotic twin pregnancies although only ~30% of a...
Article
Fetal enteric duplication cyst
Fetal enteric duplication cysts are enteric duplication cysts presenting in utero.
Pathology
They result from an abnormal recanalization of the gastrointestinal tract. They comprise of a two-layer smooth muscle wall and an internal epithelium of a respiratory or intestinal type. These cysts ma...
Article
Ectopic pregnancy
Ectopic pregnancy refers to the implantation of a fertilised ovum outside of the uterine cavity.
Epidemiology
The overall incidence has increased over the last few decades and is thought to affect 1-2% of pregnancies. The risk is as high as 18% for first-trimester pregnancies with bleeding 15....
Article
Fetal hepatomegaly
Fetal hepatomegaly (or more simply an enlarged fetal liver) can occur in number of situations. It can occur with or without fetal splenomegaly.
Pathology
Etiology
in utero infections: the commonest cause
fetal cytomegalovirus infection (CMV) 3
fetal parvovirus B19 infection
in utero syph...
Article
Spina bifida
Spina bifida is a type of neural tube defect/spinal dysraphism which can occur to varying degrees of severity. It is often considered the most common congenital CNS malformation.
Terminology
Spina bifida in its strictest sense means defective fusion of the vertebral posterior elements, leading...
Article
Pregnancy of unknown location
The term pregnancy of unknown location (PUL) is assigned when neither an intrauterine pregnancy (IUP) or an ectopic pregnancy is identified on transvaginal ultrasound in the context of a positive pregnancy test.
Clinical presentation
pelvic pain
vaginal bleeding
positive pregnancy test
Path...
Article
Gestational sac
The gestational sac is the first sign of early pregnancy on ultrasound and can be seen with endovaginal ultrasound at approximately 3-5 weeks gestation when the mean sac diameter (MSD) would approximately measure 2-3 mm in diameter.
A true gestational sac can be distinguished from a pseudogesta...
Article
Inter twin membrane
The intertwin membrane refers to a membraneous separation between two fetuses in a twin pregnancy. Depending on the chorionicity and amnionicity, the membrane may have a number of layers
dichorionic diamniotic (DCDA) pregnancy
composed of two chorionic and two amniotic layers
usually has a t...
Article
Dichorionic diamniotic twin pregnancy
A dichorionic diamniotic (DCDA) twin pregnancy is a type of twin pregnancy where each twin has its own chorionic and amniotic sacs. This type occurs most commonly with dizygotic twins, but may also occur with monozygotic twin pregnancies. This type of pregnancy may have characteristic findings o...
Article
Decidual reaction
A decidual reaction is a feature seen in very early pregnancy where there is thickening of the endometrium around the gestational sac, which is seen as an echogenic rim on ultrasound. A thin decidual reaction of <2 mm is considered one of the features suggestive of an anembryonic pregnancy 2. A ...
Article
Interstitial ectopic pregnancy
Interstitial ectopic pregnancy, also known as intramural ectopic pregnancy, is an important type of ectopic pregnancy which occurs in the proximal portion of the fallopian tube that lies within the muscle wall of the uterus. This is type of ectopic is associated with higher risks of rupture and ...
Article
Turner syndrome
Turner syndrome, also known as 45XO or 45X, is the most common of the sex chromosome abnormalities in females.
Epidemiology
The incidence is estimated at 1:2000-5000 of live births, although the in utero rate is much higher (1-2% of conceptions) due to a significant proportion of affected fet...
Article
Isolated cleft palate
An isolated cleft palate is a type of facial cleft. This is a much rarer occurrence than a cleft lip +/- palate and is thought to represent a different pathological entity.
Epidemiology
The estimated incidence is at ~1 per 2000-2500 pregnancies 4-5. There may be a slight female predilection 4....
Article
Fetal ventriculomegaly (differential)
Fetal ventriculomegaly (ventricle width >10 mm) is an important finding in itself and it is also associated with other central nervous system abnormalities. For more information, see the main article fetal ventriculomegaly.
Differential diagnosis
Fetal ventriculomegaly can be thought of in ter...
Article
Anembryonic pregnancy
Anembryonic pregnancy is a form of a failed early pregnancy, where a gestational sac develops, but the embryo does not form.
Terminology
The term blighted ovum is synonymous with this but is falling out of favor and is best avoided.
Clinical presentation
The patient may be asymptomatic, pr...
Article
Acrania anencephaly sequence
Acrania anencephaly sequence or acrania–exencephaly–anencephaly sequence is the progression from a relatively normal-appearing exposed brain due to an absent cranium (acrania) to an amorphous brain mass (exencephaly) to no recognisable brain tissue (anencephaly) 1.
Epidemiology
The acrania ane...
Article
Fetal ventriculomegaly
Fetal ventriculomegaly refers to the presence of dilated cerebral ventricles in utero.
Important in itself, it is also associated with other CNS anomalies.
Epidemiology
Using the sonographic cut-off criteria (see radiographic features below), the estimated prevalence may be at ~0.9% of all pr...
Article
Chorioamnionitis
Chorioamnionitis refers to infection of the chorion and amnion during pregnancy.
Epidemiology
Chorioamnionitis affects an estimated 2-4% of term deliveries and 40-70% of preterm deliveries 1.
Clinical presentation
Clinically, chorioamnionitis can present with the following maternal signs and...
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