Hypoplastic Left Heart Syndrome

WHAT IS IT? 

Hypoplastic left heart syndrome (HLHS) can be diagnosed prenatally, using ultrasound  

  • There are 4 chambers (sections) that make up the heart 
    • Two ventricles (lower chambers) and two atria (upper chambers)   
    • HLHS will appear on an ultrasound report when the lower chamber of the left side of the heart – the left ventricle – is smaller than expected 
  • If the left ventricle is not well developed, blood may not flow normally out of the heart and through the aorta to the rest of the baby   
  • 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

(CLICK IMAGE TO ENLARGE)

RA: Right Atrium | LA: Left Atrium | RV: Right Ventricle | LV: Left Ventricle | TV: Tricuspid Valve | MV: Mitral Valve | SVC: Superior Vena Cava | Ao: Aorta | MPA: Main Pulmonary Artery

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for Your pregnancy   

  • Further ultrasound to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal  ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any genetic changes that could explain this finding  
  • Consultation with other specialists, including  
    • Maternal Fetal Medicine (MFM) experts, pediatric cardiologists, and surgeons, to discuss potential surgical repair and appropriate setting for delivery 
    • Other specialists who deal with children who may need specialized nursery care at birth, who can provide you with more information about what to expect  
    • Genetic services  

UNDERLYING CAUSE: 

  • 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 
    • If no other findings appear on ultrasound, it is less likely to be associated with a genetic syndrome  
  • Genetic counselors are experts at communicating and educating about birth defects and can provide valuable help in understanding whether there is risk to future children or other family members

KEY POINTS: 

  • 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  
    • Knowing before birth can be very helpful to ensuring a proper pregnancy and delivery plan is in place  
    • Unfortunately, although surgeries or even heart transplant may be available for some children, HLHS is still associated with a significant decrease in survival and high complication rates
  • HLHS is considered a ‘critical congenital heart defect’ which means intervention after birth will be required
    • A ‘multidisciplinary’ approach will ideally include high risk obstetrics, neonatology, genetics and pediatric cardiology teams 

Learn More – Primary Sources: 

CDC: Facts About Hypoplastic Left Heart Syndrome 

CDC: Facts about Critical Congenital Heart Defects 

NORD: Hypoplastic Left Heart Syndrome

GARD: Hypoplastic Left Heart Syndrome

MedlinePlus: Critical Congenital Heart Disease  

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Renal Pyelectasis on Prenatal Ultrasound

WHAT IS IT?  

  • Renal pyelectasis (also called hydronephrosis or dilation) describes the condition where the tube that carries urine from the fetal kidney to the bladder is distended and wider than expected
    • Diagnosis is based on prenatal ultrasound measurements 
  • Renal pyelectasis is seen in 1 to 3 per 100 pregnancies during second trimester  
  • Most cases will resolve on their own prior to delivery  

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound(s) to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’
  • If no other fetal abnormalities are seen 
    • Your obstetric provider may offer screening for Down syndrome and other chromosomal disorders if not already done  
    • If the screening test for Down syndrome does not show increased risk, further genetic workup is not necessary  
      • Another ultrasound later in pregnancy can be done to see whether the renal pyelectasis has cleared up and the tube is back to normal size  
    • If the Down syndrome screening result shows increased risk for a fetal chromosomal problem 
      • Referral for genetic counseling and consideration of diagnostic testing options, such as amniocentesis or chorionic villus sampling (CVS), is advised to confirm whether or not a genetic problem is actually present  

KEY POINTS: 

  • Renal pyelectasis is more commonly observed in a male fetus 
  • If the ultrasound is otherwise normal and screening tests do not show an increased risk for Down syndrome, then additional genetic follow-up is not absolutely indicated 
  • If the follow-up ultrasound later in pregnancy shows that the distention is still present, referral to pediatric specialists may be needed to plan follow up after delivery  
    • Many children can be managed without surgery and in some cases, renal pyelectasis will clear up after delivery  
    • If the distention does not correct, it is helpful to know early as children will benefit from close follow up to ensure kidneys develop normally  

Learn More – Primary Sources: 

American College of Obstetrics and Gynecology – Ultrasound exams

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests

Australia’s Centre for Genetics Education – Overview of Prenatal Testing Factsheet

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Transposition of the Great Arteries

WHAT IS IT? 

Transposition of the Great Arteries (TGA) is a serious heart condition that can be detected using prenatal ultrasound, although it can be difficult to identify and may not be diagnosed until after delivery   

  • In a normal heart
    • The pulmonary artery carries deoxygenated (low oxygen) blood to the lungs
    • Oxygenated (high oxygen) blood returns from the lungs to the left side of the heart
    • From the left side of the heart, the oxygenated blood is pumped through the aorta 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)
    • The aorta, which usually arises from the left (oxygenated) side of the heart, is now exiting the right side
    • The aorta now carries deoxygenated blood (instead of normal oxygenated 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

(CLICK IMAGE TO ENLARGE)

RA: Right Atrium | LA: Left Atrium | RV: Right Ventricle | LV: Left Ventricle | TV: Tricuspid Valve | MV: Mitral Valve | SVC: Superior Vena Cava | Ao: Aorta | MPA: Main Pulmonary Artery 

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any genetic changes that could explain this finding  
  • Consultation with other specialists, including  
    • Maternal Fetal Medicine (MFM) experts, pediatric cardiologists, and surgeons, to discuss potential surgical repair and appropriate setting for delivery 
    • Other specialists who deal with children who may need specialized nursery care at birth, who can provide you with more information about what to expect  
    • Genetic services 

UNDERLYING CAUSE: 

  • In most cases, a cause is not found, however some genetic syndromes may rarely be associated with TGA, especially in the setting of other fetal problems
    • If no other findings appear on prenatal ultrasound, it is less likely to be associated with a genetic syndrome  
  • Genetic counselors are experts at communicating and educating about birth defects and can provide help in understanding TGA and whether there is risk to future children or other family members 

KEY POINTS: 

  • TGA is sometimes referred to as Transposition of the Great Vessels (TGV) 
  • TGA is considered a ‘critical congenital heart defect’ and therefore, a multidisciplinary approach is required following prenatal diagnosis  – including high risk obstetrics, neonatology, genetics and pediatric cardiology team 
    • Knowing before birth can be very helpful to ensuring a proper pregnancy and delivery plan is in place 

Learn More – Primary Sources: 

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

CDC: Facts about Critical Congenital Heart Defects 

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Ventricular Septal Defect

WHAT IS IT? 

A ventricular septal defect (VSD) describes a “hole” in the wall/septum between the two major heart chambers (sections) and may be detected during pregnancy using ultrasound  

  • There are 4 chambers that make up the heart 
    • Two ventricles (lower chambers) and two atria (upper chambers)   
    • VSD will appear on an ultrasound report when there is a ‘hole’ or connection between the right and left ventricle  
  • Depending on the size of the hole and other findings on ultrasound, symptoms can range from mild to severe 
    • Many smaller holes will close on their own  
  • VSD is the most common cause (approximately 50%) of all congenital heart defects
  • VSD alone, without any other abnormal findings, is estimated to occur in approximately 4 out of every 10,000 babies  
    • Most VSDs will be isolated without other serious findings 
    • Isolated VSDs account for 20% of all birth defects

Ventricular Septal Defect

 

(CLICK IMAGE TO ENLARGE)

RA: Right Atrium | LA: Left Atrium | RV: Right Ventricle | LV: Left Ventricle | TV: Tricuspid Valve | MV: Mitral Valve | SVC: Superior Vena Cava | Ao: Aorta | MPA: Main Pulmonary Artery   

WHAT TO EXPECT:

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound(s) to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any genetic changes that could explain this finding  
  • Consultation with other specialists, including  
    • Maternal Fetal Medicine (MFM) experts, pediatric cardiologist and surgeons, to discuss potential surgical repair and appropriate setting for delivery 
    • Other specialists who deal with children who may need specialized nursery care at birth, who can provide you with more information about what to expect  
    • Genetic services 

UNDERLYING CAUSE: 

  • In most cases, a cause is not found, however some genetic syndromes may be associated with VSD, especially in the setting of other fetal problems seen on ultrasound
    • If no other findings appear on ultrasound, it is less likely to be associated with a genetic syndrome  
    • May be associated with Down syndrome or 22q11.2 deletion syndrome as well as more rare disorders  
  • Genetic counselors are experts at communicating and educating about birth defects and can provide help in understanding more about VSD and whether is risk to future children or other family members  

KEY POINTS: 

  • Further expert fetal imaging including fetal echocardiography is valuable to determine whether finding is isolated, as well as to ensure that a proper pregnancy and delivery plan is in place

Learn More – Primary Sources: 

CDC: Facts About Ventricular Septal Defect 

NORD: Ventricular Septal Defects

American College of Obstetrics and Gynecology – Ultrasound Exams

American Heart Association

Children’s Hospital of Philadelphia

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Tetralogy of Fallot

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 to 10% of all congenital heart defects 

  • TOF derives its name (‘tetra’logy) from being a combination of 4 serious heart disorders that together cause abnormal blood flow that can be very dangerous if not diagnosed and managed appropriately 
  • Prenatal diagnosis of TOF using ultrasound can allow for appropriate planning  
  • There are 4 chambers (sections) that make up the heart 
    • Two ventricles (lower chambers) and two atria (upper chambers)   
    • The problems seen on ultrasound include abnormal development of the right ventricle and the vessels that carry blood out of the heart, as well as a hole in the heart between the two ventricles    
  • The heart abnormalities in TOF means that the baby at birth will not have normal levels of oxygen in the blood flowing to the rest of the body 
    •  Low blood oxygen levels result in babies having a blue tinge to their skin, called cyanosis 
    • Lack of sufficient oxygen at birth can results in multiple problems if TOF is not appropriately managed and corrected    

Tetralogy of Fallot

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

(CLICK IMAGE TO ENLARGE)

RA: Right Atrium | LA: Left Atrium | RV: Right Ventricle | LV: Left Ventricle | TV: Tricuspid Valve | MV: Mitral Valve | SVC: Superior Vena Cava | Ao: Aorta | MPA: Main Pulmonary Artery 

WHAT TO EXPECT:

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound(s) to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal  ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any genetic changes that could explain this finding  
  • Consultation with other specialists, including  
    • Maternal Fetal Medicine (MFM) experts, pediatric cardiologist, and surgeons to discuss potential surgical repair and appropriate setting for delivery 
    • Other specialists who deal with children who may need specialized nursery care at birth, who can provide you with more information about what to expect  
    • Genetics services  

UNDERLYING CAUSE: 

  • In most cases, a cause is not found, however some genetic syndromes may be associated with TOF 
    • 22q11.2 deletion syndrome and Down syndrome are examples of genetic disorders associated with TOF  
    • Genetic counselors are experts at communicating and educating about birth defects and can provide help in understanding more about TOF and whether there is risk to future children or other family members

KEY POINTS: 

  • TOF may be diagnosed prenatally on ultrasound  
  • Infants may require multi-step operative procedures after birth, with the goal of restoring function  
    • Knowing before birth can be very helpful to ensuring a proper pregnancy and delivery plan is in place  
  • TOF is considered a ‘critical congenital heart defect’ 
    • A likelihood of surgery and intensive management and procedures during the first year of life 
    • A multidisciplinary approach is required if prenatal diagnosis of TOF is made – including high risk obstetrics, neonatology, genetics and pediatric cardiology teams

Learn More – Primary Sources: 

CDC: Facts about Tetralogy of Fallot 

CDC: Facts about Critical Congenital Heart Defects 

NORD: Tetralogy of Fallot

GARD: Tetralogy of Fallot 

MedlinePlus: Critical Congenital Heart Disease 

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Second Trimester Nuchal Fold

WHAT IS IT?

The nuchal fold (NF) thickness is a measurement performed on prenatal ultrasound, and is the distance from the outer edge of the bone at the back of the head to the outer edge of the overlying skin. A nuchal fold thickness is only performed in the second trimester and should not be confused with a first trimester nuchal translucency (NT) measurement.

WHAT TO EXPECT:

  • The nuchal fold seen on ultrasound will be present in every pregnancy and the measurement will vary even among normal pregnancies, within a certain range
  • However, a measurement of 6mm or greater (almost a quarter of an inch) in the in the 2nd trimester is an independent risk factor for fetal abnormalities and requires referral and further follow up

Your doctor may suggest the following to determine the best management plan for our pregnancy

  • Further ultrasound(s) to look for any additional problems that may require attention
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’
  • Referral to genetic counseling services and consideration of diagnostic testing options such as amniocentesis or chorionic villus sampling (CVS) to confirm whether or not an underlying genetic problem is present (see ‘Related Topics’)
  • Most professional societies, including SMFM and ACOG recommend offering invasive testing using microarray in the setting of fetal structural anomalies seen on prenatal ultrasound

KEY POINTS:

  • Nuchal fold is sometimes confused with nuchal translucency
    • They both seen on prenatal ultrasound behind the neck/head of the developing baby
    • Measurements that are larger than normal can be associated with Down syndrome and other genetic problems and therefore, follow up is recommended
    • Note: In most cases, if there are no other findings, the baby will likely be normal at birth

Learn More – Primary Sources:

American College of Obstetrics and Gynecology – Ultrasound exam

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests

Australia’s Centre for Genetics Education – Overview of Prenatal Testing Factsheet

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Short Femur on the Second Trimester Ultrasound Report

WHAT IS IT? 

A short femur, or upper leg bone, will appear on a prenatal ultrasound report when the measurement of the bone is smaller than expected for a particular gestational age.  

  • Femur length is one of the key measurements used to measure a baby’s growth during pregnancy and is therefore part of a standard ultrasound in the second trimester 
  • The length of the baby’s femur will change and grow over time, and while there is an average measurement, some babies will have longer bones, and some shorter 
  • If no other unusual or abnormal findings appear on ultrasound, most babies will be normal at birth  
  • The finding of a short femur may be associated with chromosomal abnormalities such as Down syndrome, overall slow growth (baby is generally measuring small on ultrasound) or disorders that specifically affect bone growth 

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound(s) to look for any additional problems that may require attention, with special attention to the other bones 
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’  

If additional problems are seen on ultrasound 

  • Next steps may include referral to other specialties (for example, pediatrics and maternal-fetal medicine) to help develop a management plan to provide the best outcome possible 
  • Genetic services may also sometimes be offered depending on the specific situation
    • Genetic counselors are experts at communicating unusual ultrasound findings during pregnancy and can provide help in understanding risks and appropriate follow up, including possible tests, that may be of benefit in determining the underlying cause  

If no other fetal abnormalities are seen 

  • Your obstetric provider may offer screening for Down syndrome and other chromosomal disorders if not already done  
  • If the screening test for Down syndrome does not show increased risk, further genetic workup is not necessary  
    • Another ultrasound later in pregnancy can be done to follow up on the bone measurements  
  • If the Down syndrome screening result shows increased risk for a fetal chromosomal problem 
    • Referral for genetic counseling and consideration of diagnostic testing options such as amniocentesis or chorionic villus sampling (CVS) is advised to confirm whether or not a genetic problem is actually present  

KEY POINTS: 

  • If fetal chromosome screening test is ‘screen negative’ (no increased risk for chromosome problems such as Down syndrome) and no other findings are seen on ultrasound, most babies will be normal at birth 
  • An expert ultrasound evaluation is critical to rule out other problems and may be used to follow the baby’s growth during pregnancy  

Learn More – Primary Sources: 

American College of Obstetrics and Gynecology – Ultrasound exams

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests  

Australia’s Centre for Genetics Education – Overview of Prenatal Testing Factsheet  

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Ashkenazi Jewish Background and Genetic Carrier Screening

WHAT IS IT?   

Professional organizations recommend testing individuals of Ashkenazi (Central/Eastern European) Jewish (AJ) heritage who are pregnant or considering pregnancy   

  • AJ screening entails offering a group of genetic tests often called ‘panels’  
  • All people carry a few variants (changes in their DNA, also called ‘mutations’) that may impair the function of an important enzyme or other types of proteins 
  • Thankfully, all genes come in pairs and for many disorders, as long as one copy is working, enough protein is available to maintain heath
    • A ‘carrier’ describes someone who has a serious change in only one copy of a gene pair  
    • An individual is ‘affected’ when both gene copies, one inherited from the mother, the other from the father, both have a significant DNA change
    • With both gene copies damaged, not enough normal protein is available and disease will follow
    • Disorders that require both copies of a gene to be damaged demonstrates an autosomal ‘recessive’ inheritance pattern
    • There are some disorders where only one gene copy needs to be damaged to result in illness and demonstrates an autosomal ‘dominant’ inheritance pattern

What to Expect  

  • ACOG guidelines recommend, at a minimum, to offer screening for the following disorders when offering genetic testing to those of Ashkenazi Jewish background 
    • Tay Sachs Disease  
    • Cystic Fibrosis 
    • Canavan disease 
    • Familial Dysautonomia 
  • While these disorders have different signs and symptoms, all may have some serious consequences for a newborn baby  
  • One of the benefits of testing is that if a baby is affected, the appropriate medical/surgical team can be prepared and parents will know what to expect as a pregnancy management plan is developed 
  • ACOG has now included other disorders that ‘should be considered’ and can be further discussed before or during pregnancy  

Additional Clinical Considerations 

  • Both partners can be tested at the same time if the patient is pregnant and timing is a concern 
  • If only one member of the couple is of Ashkenazi Jewish background, it is best to test that individual first, if possible 
  • One Jewish grandparent is sufficient for testing  
    • If patient is unsure of background, offer testing 
  • Even if tested before, it is best to review previous tests to see if any new disorders may have been added  

KEY POINTS: 

  • Some of these disorders may range from mild to very serious  
    • For example, cystic fibrosis can have relatively mild signs and symptoms or require multiple medications and supportive care 
  • Even if a screening report comes back without finding a significant DNA change, genetic tests are not perfect and can still miss an important mutation 
    • A ‘negative result’ (a report without a finding of a mutation) reduces the risk, but can not guarantee a genetic disorder or birth defect is not present
  • A carrier of an autosomal recessive disorder is healthy but has a risk of passing the mutation to her offspring 
  • Genetic counseling should be available for anyone who requests further information 
  • Genetics tests are always ‘offered’ – an individual always has the right to say ‘no’  

When both partners are identified as carriers, there is a 25% (1 in 4) chance that the fetus is carrying both mutations 

  • Prenatal diagnosis with amniocentesis or chorionic villus sampling should be offered 
  • Preimplantation Genetic Diagnosis (PGD) could be considered in couples when both are carriers for the same condition 
  • Carriers should consider informing other family members, as other relatives may be at risk as well
    • Genetic professionals can be very helpful in explaining why other family members may be at risk and how best to communicate this information

Testing for those of Jewish but non-Ashkenazi heritage 

  • There are no guidelines specifically for Jews of Sephardic (descending from the Iberian/Spanish peninsula) or Mizrahi (Middle East, North Africa, Central Asia) heritage
  • Genetic testing panels that are comprehensive for Jewish individuals, regardless of area of origin, are now available and include over 90 disorders  

Learn More – Primary Sources: 

ACOG FAQs:  Prenatal Carrier Screening  

The Norton & Elaine Sarnoff Center for Jewish Genetics 

The Nicklaus Children’s Hospital Victor Center for the Prevention of Jewish Genetic Diseases 

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

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Nuchal Translucency and First Trimester Screening

WHAT IS IT? 

Nuchal translucency (NT) describes a fluid filled space seen behind the fetal neck on ultrasound and is obtained during a first trimester ultrasound.  This fluid filled space, usually a normal finding, represents fluid that is circulating around the fetus (developing baby) early in pregnancy.

  • While every fetus will have this NT space, measurements that are larger than expected place the pregnancy at higher risk for certain chromosomal problems, such as Down syndrome and Turner syndrome 
    • Other genetic syndromes have also been associated with larger NT  
  • A precise measurement of this space is an important part of standard screening for fetal chromosomal problems, including Down syndrome   
    • An NT ultrasound measurement is usually done in the first trimester between 10 0/7 and 13 6/7 weeks of pregnancy 
    • A blood sample is taken from the mother to check for certain blood protein levels (two common proteins that are usually measured are the hCG and PAPP-A proteins)
    • The NT size is combined with the information from the maternal blood sample to provide an adjusted risk for fetal Down syndrome (and sometimes other chromosomal problems)
  • Standard screening can only provide a risk assessment and can not tell for sure if a baby will be born with Down syndrome
    • Even if a test returns higher risk, it does not necessarily mean the baby will have Down syndrome
    • The purpose of this screening test is to help identify which pregnant women may be at higher risk and, therefore, benefit from further follow up and counseling   

WHAT TO EXPECT:  

  • The fluid filled space that is measured on ultrasound will be present in every pregnancy and will vary even among normal pregnancies, within a certain range  
  • However, a measurement 3.0 millimeters (approximately a tenth of an inch) or greater in the first trimester is an independent risk factor for fetal abnormalities and requires referral and further follow up  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Further ultrasound to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal ‘echocardiogram’  
  • Referral to genetic counseling services and consideration of diagnostic testing options such as amniocentesis or chorionic villus sampling (CVS) to confirm whether or not an underlying genetic problem is indeed present  

KEY POINTS: 

  • While more commonly associated chromosomal issues include Down syndrome and Turner syndrome, an enlarged NT can also be associated with other genetic syndromes, especially if other abnormalities are seen on ultrasound (for example, heart or kidney problems)  

Note: Professional programs exist for credentialing purposes that also provide education and ongoing quality review to ensure optimal NT screening performance 

Learn More – Primary Sources: 

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests

Australia’s Centre for Genetics Education – Overview of Prenatal Testing Factsheet  

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

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Gastroschisis – What Does it Mean?

WHAT IS IT? 

  • Gastroschisis is the presence of bowel loops floating in the amniotic fluid outside the abdomen  
  • There is no membrane covering the bowel loops, therefore organs are exposed to amniotic fluid and can be damaged 
  • The opening in the abdomen is usually just off to the side of where the umbilical cord connects
  • Incidence is approximately 1 in 1800 births per year in USA 

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Detailed ultrasound to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal  ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any changes in the chromosome pattern that could explain this finding  
  • Consultation with other healthcare professionals, including  
    • Pediatric surgeons, to discuss potential surgical repair and appropriate setting for delivery 
    • Maternal Fetal Medicine and Pediatric specialists who deal with bowel issues in children can provide you with more information about what to expect  
    • Genetics services (see below in ‘Underlying Cause’, below) 

UNDERLYING CAUSE:

  • Genetics  
    • Chromosomal abnormalities are not typically seen, especially if no other findings are seen on ultrasound 
    • Cause of gastroschisis is often unknown and likely is the result of many genes combined with environment  
  • Genetic counselors are experts at communicating and educating about birth defects and can provide help in understanding what to expect and whether there is risk to future children or other family members 

KEY POINTS:   

  • Prenatal screening and detection are available with the following tests during pregnancy  
    • Alpha-fetoprotein, a protein made by the fetal liver, is elevated  
      • If measured in the mother’s blood, the test is called MSAFP (Maternal Serum AFP)  
      • If measured in the amniotic fluid, the test is called AFAFP (Amniotic Fluid AFP)   
    • Prenatal ultrasound 
  • Research suggests better outcomes at perinatal centers that also include surgical teams capable of definitive operative management and neonatal intensive care availability 

Learn More – Primary Sources: 

CDC: Facts about Gastroschisis 

US NLM MedlinePlus: Gastroschisis 

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests  

American College of Obstetrics and Gynecology – Prenatal Genetic Diagnostic Tests  

American College of Obstetrics and Gynecology – Ultrasound Exams

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.

Omphalocele Explained

WHAT IS IT? 

  • Omphalocele, or exomphalos, is the protrusion of internal organs (may include intestines, liver and other abdominal organs) through the abdominal wall of the fetus and has a thin covering 
    • Occurs where the umbilical cord  attaches to abdomen  
  • Abdominal organs are normally found outside the body between 6 to 10 weeks of development  
    • Omphalocele occurs when the organs fail to return to the abdomen at the end of the first trimester  
  • Estimated to occur in approximately 1 in 5000 births 

WHAT TO EXPECT:  

Your doctor may suggest the following to determine the best management plan for your pregnancy   

  • Detailed ultrasound to look for any additional problems that may require attention  
    • Recent advances in ultrasound technology allow for improved visualization of the fetal anatomy, including the heart  
    • A specialized examination of the fetal heart is called a fetal  ‘echocardiogram’  
  • Amniocentesis or chorionic villus sampling (CVS) using microarray technology (see Related Topics below) to find out if the baby has any changes in the chromosome pattern that could explain this finding  
  • Consultation with other healthcare professionals, including  
    • Pediatric surgeons, to discuss potential surgical repair and appropriate setting for delivery 
    • Maternal Fetal Medicine and Pediatric specialists who deal with bowel issues in children can provide you with more information about what to expect  
    • Genetics services (see below in ‘Underlying Cause’, below) 

UNDERLYING CAUSE:

  • Genetics: Chromosomal abnormalities may be as high as 50%  
    • Risk of chromosomal problems in the fetus is increased if other abnormalities are seen on ultrasound   
    • Trisomy 18 (an extra chromosome 18) is the most commonly identified chromosome problem  
  • Often associated with cardiac and/or neural tube defects such as spina bifida 
  • Cause of omphalocele is often unknown   
  • Genetic counselors are experts at communicating and educating about birth defects and can provide help to you and your family in understanding what to expect and whether there is risk to future children or other family members  

KEY POINTS: 

  • Prenatal screening and detection are available with the following tests during pregnancy  
    • Alpha-fetoprotein, a protein made by the fetal liver, is elevated  
      • If measured in the mother’s blood, the test is called MSAFP (Maternal Serum AFP)  
      • If measured in the amniotic fluid, the test is called AFAFP (Amniotic Fluid AFP)   
    • Prenatal ultrasound 
  • If an omphalocele is identified on ultrasound very early in pregnancy, it may be normal and the intestines will return to the abdomen by 12 weeks gestation  

Learn More – Primary Sources: 

CDC: Facts about Omphalocele  

US NLM Medline Plus: Omphalocele 

American College of Obstetrics and Gynecology – Prenatal Genetic Screening Tests  

American College of Obstetrics and Gynecology – Prenatal Genetic Diagnostic Tests  

American College of Obstetrics and Gynecology – Ultrasound exams

AIUM–ACR–ACOG–SMFM–SRU Practice Parameter for the Performance of Standard Diagnostic Obstetric Ultrasound Examinations

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 

The DNA@ObG entries are meant for healthcare providers to share with patients as an educational tool. They are not intended as and do not constitute or substitute for medical or healthcare advice or diagnosis, and may not and should not be used for such purposes. Individuals should always consult with a qualified healthcare provider about their specific circumstances, including before starting or stopping any treatment, medical or otherwise. DNA@ObG content via this web site is provided with the understanding that The ObG Project is not engaged in rendering medical, counseling, legal, or other professional services or advice.