Abnormal findings in first trimester

 

Abnormal findings in first trimester 

Gestational sac Abnormalities 

1. Anembryonic pregnancy: (Gestational Sac with Mean Sac Diameter 16 to 24 mm and No Embryo and yolk sac)

2. Empty-amnion sign

3. Collapsed Gestational Sac 

4. Empty Gestational Sac /Blighted Ovum

(Gestational Sac with Mean Sac Diameter >25 mm and No Embryo seen)

5. Irregular Gestational Sac Shape 
6. Small Gestational Sac 
7. Low Position of the Gestational Sac
8. Double Sac Sign Absence 
9. Multiple Gestational Sacs Without Embryos
10. Gestational Sac with Echogenic Fluid 
11. Gestational Sac in an Ectopic Pregnancy (Pseudo gestational Sac) 

Yolk sac abnormalities 

1. Enlarged Yolk Sac

2. Small Yolk Sac

3. Irregular or Misshapen Yolk Sac

4. Echogenic Yolk Sac

5. Absence of Yolk Sac

6. Calcified Yolk Sac

Miscarriage 

1. Threatened Miscarriage

2. Inevitable Miscarriage

3. Incomplete miscarriage/RPOC

4. Complete miscarriage

5. Missed Miscarriage (Silent Miscarriage)

7. Recurrent Miscarriage

8. Septic Miscarriage

9. Hydropic abortion

Others abnormal findings

1.Hydatidiform Molar Pregnancy (Hydatidiform)

2. Adnexal Ring of fire sign

3. Chorionic bump

4. Failure of interval growth

5. Sub chorionic hemorrhage

Abnormal Findings in a Positive NT Scan

1. Chromosomal Abnormalities

Increased NT thickness can be linked to genetic conditions such as:

i. Down Syndrome (Trisomy 21) – Most common association; NT > 3.0 mm increases the risk.
ii. Trisomy 18 (Edwards Syndrome) – Often seen with additional structural abnormalities.
iii. Trisomy 13 (Patau Syndrome) – Associated with severe birth defects.
iv. Turner Syndrome (45,X) – Affects females, often with heart defects and abnormal lymphatic development.

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2. Congenital Heart Defects (CHD)

Common Congenital Heart Defects Associated with Increased NT
Septal Defects (Atrial & Ventricular)

Ventricular Septal Defect (VSD) – Hole in the ventricular wall.

Atrial Septal Defect (ASD) – Hole in the atrial wall, affecting blood circulation.

• Hypoplastic Left Heart Syndrome (HLHS)

  • Underdevelopment of the left heart structures, leading to severe circulation issues.

• Tetralogy of Fallot (TOF)

  • Combination of four defects, including a large VSD and an obstructed pulmonary artery.

• Transposition of the Great Arteries (TGA)

  • The positions of the pulmonary artery and aorta are switched, affecting oxygenation.

• Coarctation of the Aorta

  • Narrowing of the aorta, leading to circulation problems.

• Tricuspid Atresia

  • The tricuspid valve is missing or abnormal, affecting blood flow to the lungs.

• Ebstein’s Anomaly

  • A rare defect of the tricuspid valve causing abnormal blood flow in the heart.

• Double Outlet Right Ventricle (DORV)

  • Both the aorta and pulmonary artery arise from the right ventricle, leading to oxygenation issues

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3. Genetic Syndromes & Structural Defects

• Noonan Syndrome – A genetic disorder that can cause heart defects, short stature, and facial abnormalities.

• Skeletal Dysplasias – Conditions affecting bone and cartilage development.

• Diaphragmatic Hernia – A hole in the diaphragm allowing abdominal organs into the chest cavity.

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4. Fetal Hydrops (Hydrops Fetalis)

A severe condition where abnormal fluid buildup occurs in two or more fetal compartments (e.g., lungs, abdomen, skin, heart). Causes include:

• Chromosomal abnormalities

• Heart failure

• Infections (Parvovirus B19, CMV, etc.)

• Lymphatic drainage issues