Differential Diagnosis for Fundus Felt Higher than AOG
The situation where the fundus is felt higher than the expected abdominal girth (AOG) measurement can indicate several obstetric and non-obstetric conditions. Here's a categorized differential diagnosis:
Single Most Likely Diagnosis
- Multiple Pregnancy: This is often the most common reason for a discrepancy between the fundal height and the expected gestational age, as multiple fetuses will occupy more space within the uterus than a single fetus.
Other Likely Diagnoses
- Polyhydramnios: Excess amniotic fluid can cause the uterus to be larger than expected for the gestational age, leading to a higher fundal height.
- Uterine Fibroids: Large fibroids can increase the size of the uterus, making the fundus feel higher than expected.
- Incorrect Gestational Age Dating: If the gestational age is miscalculated, the fundal height may seem higher or lower than expected.
Do Not Miss Diagnoses
- Uterine Rupture: Although rare, a uterine rupture can present with a discrepancy in fundal height due to the uterus being irregularly shaped or the presence of free fluid in the abdomen.
- Ovarian Tumor: A large ovarian tumor can be mistaken for a pregnancy or can coexist with a pregnancy, causing the fundus to feel higher than expected.
- Abdominal Mass: Any large abdominal mass (e.g., liver, spleen, or bowel-related) can push the uterus upwards, making the fundus feel higher than the expected gestational age.
Rare Diagnoses
- Molar Pregnancy: A molar pregnancy can cause the uterus to be larger than dates due to the abnormal growth of trophoblastic tissue.
- Uterine Anomalies: Certain uterine anomalies, such as a bicornuate uterus, can affect the shape and size of the uterus, potentially leading to discrepancies in fundal height measurements.
- Intra-abdominal Shunt or Other Rare Conditions: Extremely rare conditions that could potentially cause an abdominal mass or fluid accumulation, leading to a higher fundal height than expected.