Practical obstetrics info for your women's healthcare practice

Mild Cerebral Ventriculomegaly on Prenatal Ultrasound – Next Steps and Clinical Implications

CLINICAL ACTIONS:

According to SMFM recommendations, mild cerebral ventriculomegaly is identified on a prenatal ultrasound report when the atrium measures between 10-12 mm.  Next steps include

  • Detailed anatomical study
  • Refer for genetic counseling
  • Consider diagnostic testing for aneuploidy
    • ACOG/SMFM  guidance recommends offering invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound
  • Consider maternal toxoplasmosis and cytomegalovirus (CMV) testing regardless of whether the patient is aware of previous exposure
  • Consider fetal MRI for detection of associated cortical anomalies or signs of cerebral infection
    • May be of less value if a patient has already had an ultrasound examination by a professional with expertise in fetal brain imaging on ultrasound
  • Deliver based on standard clinical indications
  • If no abnormal findings detected on thorough examination, prognosis is favorable and the newborn is expected to be normal
  • Repeat ultrasound in the 3rd trimester, (30-34 weeks gestation)
    • Prognosis is better if measurement remains stable or improves/resolves
    • Serial ultrasounds unlikely to be helpful
  • Antepartum fetal testing not likely to be beneficial
  • Antiplatelet antibodies if intracranial hemorrhage also present

SYNOPSIS:

Mild/moderate ventriculomegaly may be seen in approximately 1% of fetuses. While mild cerebral ventriculomegaly may resolve or be of no consequence, clinical work-up is required to determine whether there is any physical obstruction, decreased cerebral volume or conditions that may alter production, reabsorption or cerebral spinal fluid (CSF) flow within the cerebral ventricles.  Measurements of the lateral cerebral ventricles are obtained from an axial plane at the level of the thalamic nuclei.

KEY POINTS:

  • ‘Fetal cerebral ventriculomegaly’ is present if the atrial diameter is ≥10mm and the SMFM further refines this definition as follows
    • Mild: 10-12 mm
    • Moderate: 13-15 mm
    • Severe: >15 mm
  • Ventriculomegaly is found in 0.15%-0.7% of chromosomally normal/euploid fetuses
  • When isolated, the incidence of an abnormal karyotype is 3.8% although some centers report higher rates
  • If patient opts for invasive testing, microarray is critical as copy number variants (CNVs) have been found in 8.3% of isolated cases following normal karyotype and were highly correlated with neurodevelopmental disorders
  • Ventriculomegaly is also associated with genetic syndromes, brain malformations, feto-neonatal alloimmune thrombocytopenia and congenital infections
    • Often, no cause will be found
  • Postnatal follow-up by pediatric neurologists and specialists should be considered
    • While children with a prenatal diagnosis of mild ventriculomegaly will overall have a very good prognosis, a few may still have abnormal neurodevelopment, dependent on associated anomalies and etiology
  • When only one ventricle is mildly enlarged and there are no other findings, chromosomal work up is more likely to be normal
    • There is still a risk of congenital infections (8.2%) and additional brain abnormalities (5% prenatal and 6.4% postnatal), as well as a risk of neurodevelopmental delay of 5.9%

Learn More – Primary Sources:

Mild fetal cerebral ventriculomegaly: prevalence, characteristics, and utility of ancillary testing in cases presenting to a tertiary referral center

Copy Number Variations with Isolated Fetal Ventriculomegaly

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders

ACOG Practice Bulletin No. 226: Screening for Fetal Chromosomal Abnormalities

Society for Maternal-Fetal Medicine (SMFM) Consult Series #45: Mild fetal ventriculomegaly: Diagnosis, evaluation, and management

Fetal Mild Ventriculomegaly: Still a Challenging Problem

Perinatal and Long-term Outcome in Fetuses Diagnosed With Isolated Unilateral Ventriculomegaly: Systematic Review and Meta-analysis

Locate a genetic counselor or genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Practical obstetrics info for your women's healthcare practice

Ventricular Septal Defect – Implications for the Fetus

WHAT IS IT?

  • The left and right ventricles are connected through a “hole” in the wall/septum between the two chambers
  • Most common cause of all congenital heart defects (CHDs), comprising 50% of all CHDs
  • Estimated to occur in approximately 42/10,000 babies born
  • Isolated VSD accounts for 20% of all birth defects
  • Ventricular Septal Defects (VSDs) can be a single defect or multiple involving various components of the ventricular septum
    • The ventricular septum is made up of two major morphological components, muscular and membranous, and these components are further divided depending on location relative to other heart structures

KEY POINTS:

  • Cause of VSD is often unknown, but may be associated with common genetic issues such as Down syndrome (Trisomy 21) or 22q11.2 deletion syndrome, as well as more rare disorders
  • Can range from small isolated finding that will close on its own, to complex CHD requiring surgical repair and interdisciplinary team management
  • Consider genetic consultation and option for prenatal diagnostic testing to identify potential cause as may influence management
    • ACOG guidance recommends offering invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound
  • Further expert fetal imaging including fetal echocardiography is valuable to determine whether finding is isolated, as well as to determine prognosis and perinatal management plan

    Ventricular Septal Defect

    Image credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities

Learn More – Primary Sources:

AHA Circulation Journal Review: Ventricular Septal Defects 

CDC: Facts About Ventricular Septal Defect

Locate a genetic counselor or genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Practical obstetrics info for your women's healthcare practice

Tetralogy of Fallot- A Critical Congenital Heart Defect

WHAT IS IT?

Tetralogy of Fallot (TOF) is a congenital heart defect, that occurs in approximately 1 in every 2,500 live births and accounts for 7-10% of all congenital heart defects

TOF is comprised of 4 major abnormalities:

  • Pulmonary Infundibular Stenosis: narrowing of right ventricular outflow track
  • Overriding aorta: the aortic valve is connected to both ventricles
  • Ventricular Septal Defect: the left and right ventricles are connected through a “hole”
  • Right Ventricular Hypertrophy: the right ventricular wall muscle is thicker than usual

Cause is usually unknown, but may be associated with genetic issues

Practical obstetrics info for your women's healthcare practice

Understanding Transposition of the Great Arteries

WHAT IS IT?

In a normal heart, the pulmonary artery carries deoxygenated blood to the lungs. Oxygenated blood returns to the left side of the heart and the aorta then pumps the oxygenated blood to the rest of the body. In Transposition of the Great Arteries (TGA), the pulmonary artery and aorta have changed places (i.e., they are transposed). Therefore:

  • The pulmonary artery, which usually arises from the right side of the heart and carries deoxygenated blood to the lungs, will now connect to the left side of the heart and send oxygenated blood back to the lungs
  • The aorta, which usually arises from the left (oxygenated) side of the heart, is now exiting the right side and therefore will carry deoxygenated blood to the rest of the body, bypassing the lungs
  • 5 out of 10,000 babies are born with TGA
  • TGA is referred to as a ‘cyanotic’ (lacking oxygen) defect leading to babies with bluish discoloration and shortness of breath, with symptoms dependent on whether there is any ability for the deoxygenated and oxygenated blood to mix and be delivered to the rest of the body
  • Surgery is often necessary shortly after birth, especially in the case of complete TGA (also known as d-TGA referring to ‘dextroposition’) which is considered a ‘critical congenital heart defect’
Transposition of the Great Arteries

Image credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities

KEY POINTS:

  • While TGA can be diagnosed prenatally on ultrasound, it may not always be detected
  • In the majority of cases, a cause is not readily apparent
  • In some cases, TGA can be associated with genetic abnormalities and therefore, if a prenatal diagnosis is made or suspected, referral for genetic counseling is recommended, in addition to high risk obstetrical services, neonatology and pediatric cardiology
  • TGA is sometimes referred to as Transposition of the Great Vessels (TGV)

Learn More – Primary Sources:

CDC: Facts about dextro-Transposition of the Great Arteries (d-TGA)

Circulation-AHA journal: Transposition of the Great Arteries

CDC: Facts about Critical Congenital Heart Defects

Current diagnosis and treatments for critical congenital heart defects

Fetal Growth and Neurodevelopmental Outcome in Congenital Heart Disease

Locate a Genetic Counselor or Genetics Services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist:

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Hypoplastic Left Heart Syndrome – A Summary

WHAT IS IT?

Hypoplastic left heart syndrome (HLHS) occurs when the left side of the heart fails to develop normally.  As a result:

  • The left ventricle does not develop and is too small
  • Both the mitral valve and the aortic valve may not develop appropriately or are too small to function adequately
  • The ascending aorta is not well developed
  • A connection between the atria (artrial septal defect) or patent ductus arteriosus (small vessel that connects the aorta to the pulmonary artery) may be critical to keeping a newborn alive following delivery so that blood can circulate to the rest of the baby’s body
  • 1 out of every 4,344 babies born in the U.S. have HLHS
Hypoplastic Left Heart Syndrome

Image credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities

KEY POINTS:

  • In most cases, a cause is not found, however some genetic syndromes may be associated with HLHS, especially in the setting of other fetal structural anomalies
  • HLHS may be diagnosed prenatally on ultrasound
  • Infants may require multi-step operative procedures after birth, which are not curative, but rather have the goal of restoring function
    • Complex heart findings may ultimately require heart transplant for survival
    • Despite surgical interventions, HLHS is still associated with high mortality rates
  • While hospital survival has improved over the past decades, due to decreased cardiac output, post-operative morbidity remains significant and includes
    • Arrhythmias | Bleeding | Infection | Organ dysfunction (renal/hepatic)
    • Neurologic effects including seizures and neurodevelopmental delay
  • HLHS is considered a critical congenital heart defect and as such, a multidisciplinary approach is required if prenatal diagnosis of HLHS is made – including high risk obstetrics, neonatology, genetics and pediatric cardiology team

Learn More – Primary Sources:

Re-evaluation of hypoplastic left heart syndrome from a developmental and morphological perspective

JACC White Paper: Hypoplastic Left Heart Syndrome – Current Considerations and Expectations

Editorial: Hypoplastic Left Heart Syndrome – Can We Change the Rules of the Game?

CDC: Facts About Hypoplastic Left Heart Syndrome

CDC: Facts about Critical Congenital Heart Defects

Fetal Cardiology: Changing the Definition of Critical Heart Disease in the Newborn

Locate a Genetic Counselor or Genetics Services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist:

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Duodenal Atresia – When the “Double Bubble” is Observed on Fetal Ultrasound

WHAT IS IT?

Duodenal atresia results from failure of recanalization of the duodenum after the 7th week of gestation due to an ischemic event or genetic factors.

The classic finding on ultrasound  is the “double bubble sign” which is due to dilated proximal duodenum and stomach associated with lack of bowel gas in the distal intestine.

  • The incidence of duodenal atresia is 1/5000 – 1/10,000 live births
  • Polyhydramnios is present in 80% of cases of duodenal atresia
  • Trisomy 21 / Down syndrome is present in 25-40% of cases
  • Duodenal atresia can be associated with other congenital anomalies including:
    • VATER (vertebral defects, anal anomalies, esophageal atresia and renal anomalies)
    • Malrotation
    • Annular pancreas
    • Biliary tract anomalies
    • Cardiac anomalies
    • Mandibulofacial anomalies

KEY POINTS:

  • When detected, refer for
    • Fetal echocardiogram
    • Genetics consultation
      • ACOG guidance recommends offering invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound
    • Pediatric surgery consultation
  • Long term prognosis of isolated duodenal atresia is good, with 90% survival after surgery  

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Learn More – Primary Sources:

Small Bowel Congenital Anomalies: A Review and Update

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders

Detection Rate and Sonographic Signs of Trisomy 21 Fetuses at 14-17 Weeks of Gestation

Double Bubble Sign: Duodenal Atresia and Associated Genetic Etiologies

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Cystic Hygroma: Definition, Genetics and Prognosis

WHAT IS IT?

Cystic hygroma is a large single or multilocular fluid-filled cavity located in the nuchal region, behind and around the fetal neck, which can extend the length of the fetus and can be seen on fetal ultrasound.  Cystic hygroma differs from nuchal translucency (NT).  NT is a fluid-filled space normally seen behind the fetal neck on ultrasound performed in the first trimester. Unlike cystic hygroma, NT is a normal structure where size measurement is used as a risk factor for genetic disorders.  A thick NT measurement is associated with aneuploidy and other structural anomalies.

CLINICAL ACTIONS:

  • Refer for high risk OB consultation and genetic counseling, and consider prenatal diagnostic testing
    • ACOG guidance recommends offering invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound
  • Detailed anatomic ultrasound
  • Fetal echocardiogram

SYNOPSIS:

A cystic hygroma is an anomaly of the vascular-lymphatic system formation. Failed venous-to-lymphatic connections lead to distended fluid-filled spaces and visualization of septations which may extend along the length of the fetal axis. A cystic hygroma can be seen as early as an 11-week ultrasound. Later in pregnancy, cysts may be seen on either side of the fetal neck, with a nuchal ligament running between the two structures. Aneuploidy is present in 50% of cases. There is a high rate of intrauterine fetal demise especially if hydrops is seen. However, 10 to 20% may resolve in utero in euploid fetuses.

KEY POINTS:

  • 50% likelihood of aneuploidy
    • There is evidence that cystic hygroma detected early in the first trimester (< 45 mm CRL) may have lower rates of chromosomal abnormalities that those identified later in the first trimester (43% vs 73%)
    • Most commonly Trisomy 21 / Down Syndrome, 45X and Trisomy 18
  • <20% result in a healthy live-born infant at term
  • Not to be confused with nuchal translucency (NT)
    • Fluid filled space normally seen behind the fetal neck on first trimester ultrasound
    • NT measurement is a key component of fetal aneuploidy screening

Nuchal Translucency (NT): a normal finding

Nuchal Translucency (NT) – a normal finding

Cystic Hygroma: Note septations

Cystic Hygroma: Note septations

Learn More – Primary Sources:

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders

ACOG Practice Bulletin 226: Screening for Fetal Chromosomal Abnormalities

ACOG Committee Opinion No. 682: Microarrays and Next-Generation Sequencing Technology: The Use of Advanced Genetic Diagnostic Tools in Obstetrics and Gynecology

First trimester cystic hygroma: does early detection matter?

Locate a genetic counselor or genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Prenatal Detection of Clubfoot – Key Points

Clubfoot, congenital talipes equinovarus, is one of the most common orthopedic conditions diagnosed on prenatal ultrasound with an incidence of 1-3 per 1000 at birth.

WHAT IS IT?

  • In a fetus with clubfoot, the long axis of the foot (the sole) and the tibia can be seen in the same plane on ultrasound
    • False positive rate of clubfoot diagnosed by ultrasound may be as high as 10-19%
  • 90% of clubfoot diagnoses are made in the first and second trimester
    • Detectable on ultrasound as early as 9 weeks gestation
  • Male predominance (M:F, 2:1)

Club Foot

Anatomy & Physiology, Connexions Web Site http://cnx.org/content/col11496/1.6/, Jun 19, 2013

KEY POINTS:

Underlying Causes

Genetic

  • Mendelian: Part of a genetic syndrome, especially a neuromuscular condition, such as arthrogryposis or congenital myotonic dystrophy
    • May be inherited as an autosomal dominant condition
    • Can occur in isolation
  • Chromosomal abnormality such as trisomy 18
  • Multifactorial birth defects such as neural tube defects that negatively impact fetal movement

Factors External to the Fetus

  • Environmental factors that restrict fetal movement such as
    • oligohydramnios
    • twinning
    • amniotic band syndrome

Bilateral vs. Unilateral

  • Bilateral vs. unilateral  diagnosed prenatally in an approximately 1:1 ratio
  • Bilateral more likely to be confirmed at birth compared to unilateral (87.9% vs. 65.9%)
  • Bilateral is not more likely than unilateral to be associated with additional anomalies at birth
    • Overall in singletons, 11% with isolated club foot on prenatal ultrasound had additional findings at birth

Risk of Aneuploidy:

  • Risk of aneuploidy is increased in complex club foot (additional anomalies present)
    • Complex:  approximately 30%
    • Isolated:  Between 1.7% – 3.6% (literature suggests may be associated with sex chromosome aneuploidy)
  • ACOG guidance recommends offering
    • prenatal aneuploidy screening or diagnostic testing (amniocentesis or CVS) for all pregnant women regardless of age
    • Invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound
  • If suspected or diagnosed, refer for genetic counseling, MFM and pediatric orthopedic consultation for further discussion to determine possible etiologies, clubfoot correction, surgical and nonsurgical options

Learn More – Primary Sources:

Diagnostic accuracy, work-up and outcomes of pregnancies with clubfoot detected by prenatal sonography

Outcome of prenatally diagnosed isolated clubfoot

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders

ACOG Practice Bulletin 226: Screening for Fetal Chromosomal Abnormalities

ACOG Committee Opinion No. 682: Microarrays and Next-Generation Sequencing Technology: The Use of Advanced Genetic Diagnostic Tools in Obstetrics and Gynecology

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Cleft Lip and Palate – Considerations and Discussion Points

SUMMARY:

Orofacial clefts, which include cleft lip, cleft palate or combined cleft lip and palate are the most common congenital facial malformation.

  • Prevalence of orofacial clefts is approximately 1/700
    • Cleft lip with cleft palate (most common): 50% of cases
    • Isolated cleft lip: 25%
    • Isolated cleft palate: 25%
  • Majority are paramedian: 64% unilateral | 34% bilateral
  • More common in Asians American groups
  • Less common in African Americans
  • Facial clefts result from defective fusion of the facial processes
  • Association of facial cleft with other anomalies
    • 13% of fetuses will have associated anomalies | Higher rate with bilateral and highest rate with median
  • Inheritance pattern
    • Isolated orofacial cleft typically multifactorial
    • Facial cleft may be associated with chromosomal and single gene disorders

CLINICAL ACTIONS:

Prenatal Detection

  • Detection rate of isolated cleft lip (with or without cleft palate) on ultrasound is variable across studies from 10% to 90%
    • Detection of cleft lip (with or without cleft palate) may be approximately 80%
    • Cleft palate is harder to detect and may be missed even by skilled sonographers
    • If bilateral cleft is identified, there is a higher risk for additional anomalies compared to unilateral cleft (25% to 10%, respectively)
  • Detailed prenatal anatomic ultrasound examination is recommended upon diagnosis
    • Evaluate for other anomalies to determine management and prognosis
    • Fetal echocardiogram should be considered
  • ACOG and SMFM recommend offering  diagnostic testing
    • Microarray technology should be used due to finding of fetal structural anomaly (facial cleft) on ultrasound
    • Single gene testing or exome sequencing should be discussed with a genetic counselor on an individual basis
  • MRI may be an adjunct to prenatal diagnosis of orofacial clefts if there is concern for additional anomalies or if ultrasound imaging is incomplete
  • Treatment
    • There is no prenatal treatment
    • Consider pediatric surgical referral upon diagnosis to discuss potential surgical repair and appropriate setting for delivery

Genetics

  • In most cases, there is no clear identifiable cause of cleft lip
  • However, facial clefts have been associated with genetic syndromes and chromosomal anomalies
  • Referral to genetic counseling should be offered

Multifactorial Inheritance

  • Combination of genes and environment
  • Approximately 3% to 5% chance of recurrence which is 20% to 35% fold increase over baseline
    • If no other relatives based on professional pedigree analysis, risk to siblings may be lower than 3%
  • Recurrence risk increases
    • If more than one child affected
    • With increasing severity
  • Risk to other family members
    • Second degree relatives (half-sibs, aunts/uncles and grandparents): Much lower than above
    • Third degree relatives (e.g., first cousins): Likely not above baseline risk

Single Gene Disorders

  • Autosomal dominant, autosomal recessive and X-linked dominant disorders have been associated with orofacial clefts and should be considered if other family members are affected
  • May be syndromic, i.e., appears in a recognized constellation of other clinical findings rather than as an isolated birth defect

Chromosomal Disorders (rare if no other anomalies)

  • 22q11.2 deletion syndrome
    • Submucosal Cleft Palate
  • Common autosomal trisomies
    • Trisomy 13 (associated with midline clefting)
    • Trisomy 18

Environmental Risks

  • Smoking
    • Second-hand exposure may be a risk factor
  • Alcohol consumption: Evidence not consistent
    • Binge drinking may be higher risk
  • Medications
    • Antiepileptics such as phenytoin, valproic acid
    • Folate antagonists (MTX)
  • Maternal pre-pregnancy diabetes mellitus
  • Obesity

KEY POINTS:

  • Isolated paramedian orofacial clefts without an associated genetic condition have an excellent prognosis with surgical repair
  • A median (midline) facial cleft has strong association with other anomalies and aneuploidy (Trisomy 13)
  • Mode of delivery and timing of delivery should not be impacted unless other usual obstetric indications

Learn More – Primary Sources:

CDC-Facts about Cleft Lip and Palate

SMFM Fetal Anomalies Consult Series #1: Facial Anomalies

ACOG Practice Bulletin No. 226: Screening for Fetal Chromosomal Abnormalities

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Omphalocele – An Early Ventral Wall Defect

WHAT IS IT?

  • Omphalocele, or exomphalos, is the protrusion of internal organs, which may include intestines, liver (when present=giant omphalocele) and other abdominal organs, through the ventral wall of the fetus or infant and covered by a membrane consisting of peritoneum, Wharton’s jelly, and amnion
  • Results from failure of involved organs to return to abdominal cavity from the gut tube during 6-10 weeks of development
  • Estimated to occur in approximately 1/5400 births
  • Chromosomal abnormalities may be as high as 50%
    • Increased risk of chromosomal abnormalities related to presence of other anatomic anomalies or increased nuchal translucency
    • Trisomy 18 is the most commonly identified aneuploidy
  • Often associated with cardiac and/or neural tube defects

 

Omphalocele

Image credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities

KEY POINTS:

  • Cause of omphalocele unknown in most cases. Associations demonstrated with maternal history of:
    • Smoking
    • Alcohol use in pregnancy
    • Obesity
  • Prenatal Screening and detection is available:
    • Maternal Serum AFP (MSAFP) is elevated
    • Amniotic fluid AFP (AFAFP) is elevated
    • Can be detected on prenatal ultrasound
  • If an omphalocele is identified on sonography, consider:
    • Fetal chromosomal analysis including microarray as recommended by ACOG
    • Fetal echocardiogram referral
    • Genetic counseling to help identify potential causes, recurrence risk and management plan
    • Note: physiologic omphalocele may be noted in the first trimester but resolves by 12 weeks gestation
      • Liver should never be seen outside the fetal abdomen and this finding allows the diagnosis at any time in gestation
  • Refer to pediatric surgical specialist to discuss possible surgical correction options, outcomes and long term implications
  • Develop labor and delivery plan for those who will continue the pregnancy given high risk nature of pregnancy, and coordinate with NICU and pediatric team as needed
  • ICD – 10 Code: Q79.2 

Learn More – Primary Sources: 

CDC: Facts about Omphalocele

US NLM Medline Plus: Omphalocele

Abdominal Wall Defects: Prenatal Diagnosis, Newborn Management, and Long-term Outcomes

ACOG Practice Bulletin No. 162: Prenatal Diagnostic Testing for Genetic Disorders 

Outcome of fetal exomphalos diagnosed at 11-14 weeks of gestation

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist:

Maternal Fetal Medicine Specialist Locator-SMFM

Practical obstetrics info for your women's healthcare practice

Microcephaly – Beyond the Zika Virus

WHAT IS IT? 

  • Microcephaly means “small head”, and can be used interchangeably in some instances with microencephaly, “small brain”
    • Consider abnormal development (primary microcephaly) if detected prior to 32 weeks gestation, as opposed to a degenerative condition in which normal head size becomes smaller (secondary microcephaly)

SYNOPSIS:

Microcephaly has an incidence of 2-12 in 10,000 births in the USA, and can be diagnosed prenatally via ultrasound (in second or early third trimester) or postnatally via measurement of head circumference (HC).  Microcephaly has been linked to developmental delay, seizures, as well as feeding, vision and hearing problems.  Prognosis depends on the severity of the microcephaly and whether it is associated with other anomalies.

KEY POINTS:

Definitions

SMFM – Fetal Microcephaly

  • HC ≥ 3 SD below the mean for gestational age is the recommended definition
  • HC ≥ 5 SD below the mean is a certain diagnosis

CDC – Postnatal Congenital Microcephaly

  • Definite Congenital Microcephaly
    • HC at birth < 3rd percentile for gestational age and sex
    • If HC not available at birth, HC < 3rd percentile for age and sex within the first 2 weeks of life
    • For Stillbirths and elective terminations, CDC definition based on HC at delivery < 3rd percentile for gestational age and sex
  • Possible Congenital Microcephaly
    • For Live Births: If earlier HC is not available, HC < 3rd percentile for age and sex beyond 6 weeks of life
    • For All Pregnancy Outcomes: Microcephaly diagnosed or suspected on prenatal ultrasound in the absence of available postnatal HC measurements

Management

  • If fetal HC by ultrasound is > 2 SD below the mean for gestational age, a careful evaluation of the fetal intracranial anatomy is indicated
    • If the intracranial anatomy is normal, consider follow-up in 3-4 weeks
  • When evaluating the finding of fetal microcephaly, assess for the following
    • Infectious exposures including
      • Zika virus
      • Maternal syphilis, herpes, HIV, rubella, toxoplasmosis, cytomegalovirus
    • Alcohol consumption, exposure to certain medications and/or smoking during pregnancy
    • Genetic conditions, including aneuploidy or single gene disorders
  • Many ultrasound packages report HC percentiles and not standard deviations (SD) and often the lowest reported HC measurement is <5th percentile
    • In such cases, SMFM suggests using head circumference (in millimeters) to determine SD below the mean
    • SMFM provides a table (see ‘Learn More – Primary Sources’ below) to determine the number of SD below the mean as a function of gestational age
  • Role of MRI: The SOGC Guideline states (III-A evidence)

Once fetal microcephaly is identified by ultrasound, fetal magnetic resonance imaging, when available and if potential findings are likely to alter pregnancy management, may be considered.

Fetal magnetic resonance imaging images should be reviewed by a radiologist with expertise in fetal magnetic resonance imaging.

  • Consider referral to a Fetal Maternal Medicine Specialist
  • Consider referral to Genetic Counseling, especially if microcephaly is associated with other findings
  • Consider referral to Pediatric Neurologist for review of short and long term potential outcomes for the newborn and child with microcephaly

Microcephaly

Image credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities

Learn More – Primary Sources:

Microcephaly: An Epidemiologic Analysis 

SMFM Statement- Ultrasound Screening for Fetal Microcephaly Following Zika virus Exposure

SOGC Guideline 380: Investigation and Management of Prenatally Identified Microcephaly

CDC: Zika Virus For Healthcare Providers

CDC: Areas with Risk of  Zika in the US

Serial Head and Brain Imaging of 17 Fetuses With Confirmed Zika Virus Infection in Colombia, South America

US Zika Pregnancy Registry Collaboration: Birth Defects Among Fetuses and Infants of US Women With Evidence of Possible Zika Virus Infection During Pregnancy

ACOG Committee Opinion 784: Management of Patients in the Context of Zika Virus

Locate a Genetic Counselor or Genetics services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

Locate a Maternal Fetal Medicine Specialist:

Maternal-Fetal Medicine Specialist Locator-SMFM