CPC

Regarding the finding of CPCs, these are simple cysts or fluid filled pouches inside the choroid plexus within the lateral ventricles of the fetal brain. They can be unilateral or bilateral, and size is not clinically relevant. Most resolve by about 30 weeks of gestation. They are commonly seen in healthy pregnancies, and are of no clinical significance in the vast majority of cases. However, there is an approximately 7 fold increase in the risk of trisomy 18 in the presence of CPCs. Infants with trisomy 18 typically present with multiple abnormal findings on the midtrimester ultrasound, so it is imperative to ensure a complete fetal anatomy assessment has been done.

CPCs with a Negative Screening Result

Regarding the finding of CPCs, these are simple cysts or fluid filled pouches inside the choroid plexus within the lateral ventricles of the fetal brain. They can be unilateral or bilateral, and size is not clinically relevant. Most resolve by about 30 weeks of gestation. They are commonly seen in healthy pregnancies, and are of no clinical significance in the vast majority of cases. CPCs may be associated with an increased risk of Trisomy 18. However, according to recent SOGC guidelines (JOGC 2017;39(9):805-817), isolated CPCs in the context of a negative aneuploidy screen are of no clinical significance. Infants with Trisomy 18 typically present with multiple abnormal findings on the midtrimester ultrasound, so in this case it is reassuring to note that the ultrasound report indicates no structural fetal anomalies. We did discuss the limitations of ultrasound, and that it cannot detect all birth defects, chromosome abnormalities or genetic syndromes.

Two Vessel Cord (2VC)

A two vessel cord can be related to heart and kidney defects. Defects of this nature were not seen today. Ultrasound cannot diagnose or rule out all birth defects. Consider a third trimester ultrasound to reassess fetal growth and well being, as well as to reassess placenta due to the 2VC. Two vessel cord is frequently seen in association with structural cardiac or renal anomalies. It was certainly reassuring that today's ultrasound did not reveal any structural fetal anomalies, although we did of course discuss the limitations of obstetrical ultrasound. You might wish to consider a third trimester ultrasound to reassess fetal growth and well being, as well as to reassess placenta due to the 2VC.

Increased Nuchal Transulency (NT)

NT: Increased NT can be associated with aneuploidy, structural abnormalities (such as cardiac defects, renal or genitourinary problems) or rare genetic syndromes. No additional issues were identified in the family history. Unexplained increased NT with no evidence of structural fetal anomalies or aneuploidy predicts a good outcome for the infant in greater than 96% of cases. We recommend pediatric assessment of the newborn and consult clinical geneticist if any clinical concerns.

Mild Renal Pelviectasis

Renal pelviectasis is not associated with an increased risk for aneuploidy, but should be followed up in the third trimester for evidence of hydronephrosis.

Echogenic Bowel

Echogenic bowel is associated with a 6 fold increased risk for Down syndrome, which implies a risk of 1 in ___ in this case. Echogenic bowel can also be seen in cases of congenital infection, bowel obstructions, and cystic fibrosis.

Echogenic Intracardiac Foci EICF

EICF is defined as one or more echogenic structures on or around the papillary muscle in one or both ventricles of the fetal heart. This finding is rarely associated with structural cardiac malformations, but good visualization of the 4 chamber view and outflow tracts are necessary assessments. There is an approximately 2 fold increase in the risk of trisomy 21 (Down syndrome) in the presence of an EICF. Later persistence or resolution of the EICF does not alter the risk. For this pregnancy, since the EICF is an isolated soft marker, and IPS is negative, the likelihood of Down syndrome is in the order of 1 in ____.

Anencephaly

Acrania / anencephaly is a lethal defect with virtually no chance for long-term survival. An infant with anencephaly may be stillborn or liveborn, but survival past the newborn period is rare. In most cases this is an isolated defect with multifactorial etiology, implying a recurrence risk of up to 4% for the next pregnancy. For all neural tube defects there is a 6 to 10% chance of an underlying chromosome abnormality. We offered amniocentesis for cytogenetic testing of the pregnancy to assess the potential recurrence risks for a future pregnancy or for other family members.

CCAM

The appearance of the right lung is most consistent with congenital cystic adenomatoid malformation of the lung (CCAM). The differential diagnosis includes bronchopulmonary sequestration (BPS). This is a cystic mass of abnormal lung tissue. Generally CCAMs will be stable or get smaller through gestation and the prenatal course is usually unremarkable. With large lesions, there is a risk of cardiovascular compromise leading to fetal hydrops, but that seems unlikely in this case. With any lung lesion, there is the risk of pulmonary hypoplasia, which may result in significant morbidity or mortality. CCAM is not associated with chromosomal abnormalities, and in most cases is an isolated lesion with a good prognosis. We discussed the importance of monitoring the pregnancy with serial ultrasounds and fetal echocardiogram to assess progress of the mass and cardiac function. There are centres in the USA where fetal surgery is done for some cases of fetal lung masses, but this is usually only considered in severe cases with onset of fetal hydrops or cardiac output failure.

Cleft Lip

Most facial clefts are isolated and have multifactorial etiology. Although anatomical assessment in this case is limited, we have no evidence of multiorgan involvement and therefore no indication to consider invasive testing for fetal chromosomes. Recurrence risk for isolated cleft lip with or without cleft palate is in the order of 3 to 4 %.

Cystic hygroma

Cystic hygroma can be associated with aneuploidy (ie: Turner syndrome), structural abnormalities (cardiac defects, renal or genitourinary problems), infection or rare genetic syndromes. Chance of aneuploidy is greater than 50%. Cystic hygroma can spontaneously resolve in the second trimester but the presence of hydrops indicates a poor prognosis; greater than 50% chance of miscarriage and an estimated 40% chance of perinatal moratlity.

Clubfoot

Idiopathic talipes equinovarus (club foot) occurs in 1/1000 births and has a risk for recurrenc e of ~3%. In isolation, the basis for inheritance is multifactorial and recurrence risk is based on empiric data. In association with other abnormalities the risk for chromosomal abnormalities or genetic syndromes increases to warrant invasive testing. There is a relatively high chance of associated abnormalities and care must be taken when counselling whether club foot is truly isolated. If other fetal findings present themselves then invasive prenatal testing is offered to rule out chromosomal abnormalities or gene defects through microarray. The majority of cases of clubfeet are multifactorial in nature and are not associated with other abnormalities or chromosomal aneuploidy. This was supported by the absence of additional findings on the ultrasound. Specifically, there was no evidence of a generalized neurological disorder, and no contractures or arthrogryposis involving the limbs other than the feet. Given the general limitations of ultrasound, we would, of course, recommend careful newborn assessment and Genetic consultation if clinically indicated after delivery. Cytogenetic testing can be done from a cord blood sample or a peripheral blood sample if clinically indicated at that time.

Horseshoe Kidney

Horseshoe kidney is a common developmental abnormality, commonly seen as an isolated malformation, but also known to be associated with aneuploidy. Normal renal echogenicity and normal amniotic fluid volume is somewhat reassuring for prognosis. Patient could meet with pediatric nephrologist for more information about outcomes with horseshoe kidney.

Gastroschisis

Gastroschisis is most often an isolated defect and is not associated with chromosomal aneuploidy. The differential diagnosis includes a ruptured omphalocele, but the abdominal defect in this case appears to be separate from the umbilical cord insert. The majority of cases of gastroschisis have a good outcome, but there is a need for serial ultrasounds and the potential for complications that could affect the prognosis for the baby. There is an increased risk for stillbirth or intrauterine demise with fetal gastroschisis (approximately 8%). The etiology of gastroschisis is thought to be related to vascular insult in the first trimester, and there is an association with younger maternal age and smoking during pregnancy. Cases require pediatric surgery and neonatology consultation closer to term, to learn more about surgery and outcomes for infants with gastroschisis.

Omphalocele

As an isolated finding, this has an association with chromosomal abnormalities in about 30% of cases. Surgical and pediatric outcomes depend on the underlying etiology and any associated structural anomalies, which are also frequently found in fetuses with an omphalocele. The majority of cases of isolated omphalocele have a good outcome following surgery in the newborn period, but there is the potential for complications that could affect the prognosis for the baby. Even in cases of apparently isolated omphalocele, there is an increased risk of complications leading to stillbirth or neonatal death. If there are other anomalies, then the likelihood of a chromosomal abnormality or underlying syndrome is more like 50%. There is an increased need for close fetal monitoring and surveillance with care of the pregnancy in a high risk clinic. Cases require pediatric surgery and neonatology consultation closer to term, to learn more about surgery and outcomes for infants with an Omphalocele.