What is Fetal Medicine?

Fetal medicine is a branch of medicine that includes the assessment of fetal growth and wellbeing, the maintenance of fetal health and the diagnosis of fetal illnesses and abnormalities.

As prenatal diagnosis has improved, so has our capability to diagnose problems before birth. Therefore, the fetus is increasingly becoming an independent individual, and fetal medicine is the specialty that addresses this “unborn patient.”

Fetal medicine is a relatively new specialty that often requires the expertise and input from various specialists, including obstetricians, perinatologists (also called maternal-fetal medicine specialists), neonatologists, pediatric cardiologists, pediatric surgical specialists, geneticists and others.

Fetal medicine can be arbitrarily divided into two branches: Prenatal diagnosis and Fetal treatment. Prenatal diagnosis is the ever-improving ability to detect abnormal conditions of the fetus (and to differentiate them from normal fetal development). The most common (and often first) test used for prenatal diagnosis is ultrasound. Other modalities include non-invasive and invasive screening and diagnostic studies:

A) Screening studies are relatively simple and inexpensive tests aimed at detecting all cases of a particular anomaly within a relatively large “at risk” population. Examples are screening for spina bifida and Down syndrome:

• Maternal Serum Alpha-Fetoprotein, or MSAFP, is a maternal blood test that may help detect spina bifida (also called myelomeningocele or open neural tube defect).
• Nuchal translucency is a distinct finding on ultrasound examination of the fetal neck, that may suggest the possibility of Down syndrome (but is not a very accurate test in itself).
• Adding certain blood tests (including MSAFP) increases the accuracy of the diagnosis of Down syndrome. Depending on the number of screening tests, they are referred to as “combined,” “triple” or “quadruple” tests.

B) Non-invasive diagnostic tests include:

• Maternal blood tests for specific conditions, or to look for fetal cells
• Two- and three-dimensional ultrasound
• Doppler ultrasound
• Cardiotocography and echocardiography of the fetus
• Magnetic resonance imaging (MRI)

Doppler ultrasound of the umbilical cord

MRI of the fetus

C) Invasive diagnostic tests require a form of surgical intervention, ranging from the insertion of a fine needle into the uterus under ultrasound guidance, to more invasive procedures such as fetoscopy. The most common invasive tests are:

• Amniocentesis
• Chorion villus sampling
• Umbilical cord sampling (cordocentesis, funipuncture, percutaneous umbilical blood sampling, or PUBS)

Fetal treatment or fetal therapy includes a series of interventions performed on the “sick” fetus with the aim of achieving fetal well being. These interventions include medical (i.e. non-invasive) and surgical procedures.