A 31-year-old woman, gravida 3, para 2, presents to the obstetrics clinic at 23 weeks gest… — USMLE Step 2 CK

A $31$ -year-old woman, gravida $3$ , para $2$ , presents to the obstetrics clinic at $23$ weeks gestation for a scheduled evaluation. She reports new-onset, brief, sharp, pulling pains in the bilateral lower quadrants of her abdomen. The pain occurs primarily when she stands up quickly from a seated position and resolves within a few seconds. She denies vaginal bleeding, dysuria, or regular uterine contractions. Her blood pressure is $110/66$ mm Hg, pulse is $86$ /min, and respirations are $16$ /min. Abdominal examination reveals a soft uterus with fundal height corresponding to $23$ cm. There is mild tenderness to palpation over the lateral borders of the uterus, but no guarding or rebound tenderness. Laboratory results obtained two days ago for an employer-sponsored health screening reveal the following:

Serum sodium: $131$ mEq/L
Serum creatinine: $0.5$ mg/dL
Alkaline phosphatase (ALP): $245$ U/L
Aspartate aminotransferase (AST): $22$ U/L

Urinalysis:
Specific gravity: $1.014$
Glucose: $2+$
Protein: Trace
Leukocyte esterase: Negative
Nitrites: Negative
Microscopy: $1-2$ WBCs/hpf

Based on these clinical and laboratory findings, which of the following is the most appropriate next step in management?

A
Order a $24$ -hour urine collection to quantify total protein
B
Perform a right upper quadrant ultrasound to evaluate the biliary tree
C
Administer a $50$ -g oral glucose challenge test today
Recommend a maternity support garment and routine follow-upAnswer
E
Advise free water restriction to correct the serum sodium level

Answer

Recommend a maternity support garment and routine follow-up

The patient's clinical presentation is consistent with round ligament pain, a normal physiologic consequence of the rapidly stretching uterus in the second trimester. It is classically characterized by brief, sharp, lower abdominal pain exacerbated by sudden movements. Conservative management with a maternity support garment and reassurance is the appropriate next step. Furthermore, her laboratory findings (mild hyponatremia, decreased creatinine, elevated alkaline phosphatase, trace proteinuria, and glucosuria) entirely reflect expected physiologic adaptations to pregnancy rather than underlying pathology. Consequently, no directed medical interventions or alterations to her routine prenatal care schedule are indicated.

Step-by-Step Solution

Analyze the patient's abdominal pain.

The brief, sharp pain provoked by sudden movement is classic for round ligament pain.

It is critical to differentiate physiologic musculoskeletal pain from obstetric emergencies such as placental abruption or preterm labor.

Evaluate the comprehensive metabolic panel findings.

Sodium of 131 mEq/L, Creatinine of 0.5 mg/dL, and elevated ALP are all identified as normal physiologic adaptations.

Pregnancy causes reset osmostats, increased GFR, and placental ALP production, which commonly mimic pathologic lab values.

Assess the urinalysis results.

Trace protein and 2+ glucose are normal due to increased GFR exceeding tubular reabsorption maximums; the absence of leukocyte esterase and nitrites rules out a urinary tract infection.

Determining if the urinalysis warrants early GDM screening, preeclampsia workup, or antibiotics.

Determine the appropriate management plan.

Conservative management for the pain and adherence to the routine prenatal schedule is indicated.

No pathologic processes are present to warrant early screening, imaging, or medical therapy.

Key Concept

Physiologic maternal adaptations to pregnancy

Estimated Time:1m 30s

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