What is the management plan for a fetus with Turner syndrome and a normal ultrasound?

Management of Fetal Turner Syndrome with Normal Ultrasound

For a fetus with Turner syndrome and normal ultrasound findings, close monitoring with serial ultrasounds is recommended, but no additional interventions are necessary as these cases typically have good outcomes with low risk of significant complications.

Understanding Turner Syndrome with Normal Ultrasound

• Turner syndrome with normal ultrasound represents a subset of cases that generally have better prognosis than those with abnormal ultrasound findings 1
• Fetuses with incidental diagnoses of Turner syndrome (particularly mosaic forms) associated with normal ultrasounds have a high survival rate and may have no or only mild features of Turner syndrome 1
• The absence of ultrasound abnormalities is a positive prognostic indicator, as most severe cases of Turner syndrome present with detectable ultrasound findings 2, 3

Recommended Management Protocol

Prenatal Surveillance

• Perform detailed follow-up ultrasound examinations every 4 weeks to monitor for development of any Turner syndrome-associated findings 2
• Include comprehensive assessment of:
  • Fetal cardiac anatomy (particularly looking for coarctation of the aorta, which occurs in 44.4% of Turner syndrome cases with cardiac defects) 2
  • Neck region (to monitor for development of cystic hygroma) 4
  • Fetal growth parameters 1
  • Amniotic fluid volume 2

Third Trimester Management

• Perform a detailed third-trimester ultrasound with particular focus on cardiac anatomy 1
• Consider fetal echocardiography if there is any concern about cardiac structure 2
• Plan for delivery at term in the absence of complications 1

Delivery Planning

• Notify pediatric providers of the prenatal diagnosis at the time of delivery for appropriate postnatal follow-up 1
• No special delivery considerations are needed for Turner syndrome with normal ultrasound beyond standard obstetrical care 1

Postnatal Considerations

• Arrange for postnatal evaluation by pediatric endocrinology for long-term management 1, 5
• Cardiac MRI is recommended in the postnatal period to screen for individuals at high risk for serious complications 1
• Growth-promoting therapy and pubertal induction may be needed later in childhood 1

Important Clinical Pearls

• The absence of ultrasound abnormalities significantly improves prognosis in Turner syndrome 1, 2
• Mosaic forms of Turner syndrome (45,X/46,XX) are more likely to present with normal ultrasound findings and have milder clinical manifestations 1, 5
• Common pitfall: Assuming all Turner syndrome cases require intervention - those with normal ultrasound findings generally have good outcomes with expectant management 1
• The most concerning ultrasound findings in Turner syndrome (cystic hygroma, increased nuchal translucency, cardiac defects, and hydrops) are absent in these cases, which is why the prognosis is better 4, 2, 3

Monitoring for Late-Developing Complications

• While initial ultrasound may be normal, continue surveillance as some findings may develop later in pregnancy 2
• Pay particular attention to fetal growth parameters, as growth restriction may develop later 1
• Monitor for development of cardiac abnormalities, especially coarctation of the aorta, which may be subtle or develop later 2