Normal amniotic membrane vs cystic hygroma and fetal hydrops

Differentiating between normal amniotic membrane, cystic hygroma, and fetal hydrops on ultrasound imaging in a 6-week pregnancy can be challenging, but here are some pointers:

**Normal Amniotic Membrane:**

1. Presence of a normal, clear amniotic sac.

2. Typically, a single gestational sac with a yolk sac and possibly the fetal pole visible.

3. Uniform thickness of the amniotic membrane surrounding the embryo.

4. Absence of abnormal fluid collections or masses around the developing fetus.

Normal amniotic membrane is shown in the TVS scan ultrasound images below:

**Cystic Hygroma:**

1. Large, cystic, fluid-filled structure around the fetal neck or head region.

2. The presence of septations or internal echoes within the cystic structure.

3. Abnormalities in the nuchal translucency measurement, showing increased thickness.

4. May lead to an altered appearance of the amniotic sac due to the surrounding fluid accumulation.

**Fetal Hydrops:**

1. Generalized swelling or edema in multiple fetal areas, such as the abdomen, chest, or skin.

2. Presence of fluid accumulation in two or more fetal compartments (e.g., pleural effusion, ascites).

3. Increased nuchal translucency in combination with abnormal fluid accumulations.

4. Signs of cardiac compromise, such as an enlarged heart or abnormal heart rhythms.

However, it's crucial to note that these findings might not be definitively conclusive at 6 weeks gestation. Detailed assessment by a trained sonographer or a specialist is essential for accurate diagnosis and proper management.

For more on this topic visit:

Sonography of early pregnancy