A 28-year-old G1P0 presents to your office at 18 weeks gestational age for an unscheduled visit secondary to right-sided groin pain. She describes the pain as sharp and occuring with movement and exercise. She denies any change in urinary or bowel habits. She also denies any fever or chills. The application of a heating pad helps allete the discomfo. As her obstetrician, what do you tell this patient is the most likely etiology of this pain?

**Core Concept**
The patient's presentation of sharp, exercise-induced groin pain, relieved by a heating pad, suggests a musculoskeletal or ligamentous origin. This is consistent with a diagnosis of **pubic symphysis pain**, a common condition during pregnancy due to the relaxation of pelvic joints and ligaments.

**Why the Correct Answer is Right**
The relaxation of the pubic symphysis and surrounding ligaments during pregnancy leads to increased mobility and susceptibility to injury. The patient's symptoms are exacerbated by movement and exercise, which causes micro-tears in the ligaments, resulting in pain. The application of a heating pad helps relieve the discomfort by increasing blood flow and reducing muscle spasms.

**Why Each Wrong Option is Incorrect**
**Option A:** **Ovarian torsion** is an emergency condition characterized by sudden, severe pelvic pain, often accompanied by nausea and vomiting. The patient's pain is described as sharp but not severe, and she denies any systemic symptoms.

**Option B:** **Appendicitis** typically presents with abdominal pain, fever, and leukocytosis. The patient's pain is localized to the groin, and she denies any fever or systemic symptoms.

**Option C:** **Cystitis** is characterized by dysuria, frequency, and urgency. The patient denies any change in urinary habits, making this diagnosis less likely.

**Option D:** **Round ligament pain** is a common condition during pregnancy, but it typically presents as a dull ache or sharp twinge in the lower abdomen, not the groin.

**Clinical Pearl / High-Yield Fact**
It's essential to differentiate between musculoskeletal and obstetric causes of pelvic pain in pregnant women, as the management and treatment strategies differ significantly. A thorough history, physical examination, and sometimes imaging studies are necessary to arrive at an accurate diagnosis.

**Correct Answer: D. Round ligament pain**

✓ Correct Answer: A. Round ligament pain