What lab orders are recommended for a 4-month postpartum patient with postpartum anxiety and Obsessive-Compulsive Disorder (OCD) symptoms?

Laboratory Workup for Postpartum Anxiety and OCD

For a 4-month postpartum patient presenting with anxiety and OCD symptoms, you should order thyroid function tests (TSH, free T4), complete blood count (CBC), comprehensive metabolic panel (CMP), vitamin D 25-OH, ferritin, and vitamin B12 to rule out medical causes that can mimic or exacerbate psychiatric symptoms.

Essential Laboratory Tests

Thyroid Function

• TSH and free T4 are critical because thyroid dysfunction is common postpartum and can present with anxiety, obsessive thoughts, and mood changes 1
• Postpartum thyroiditis occurs in up to 10% of women and can manifest as hyperthyroidism (anxiety, restlessness) or hypothyroidism (depression, cognitive slowing) 1

Hematologic Assessment

• Complete blood count (CBC) to evaluate for anemia, which is common postpartum and can worsen fatigue, cognitive function, and anxiety symptoms 1
• Ferritin levels should be checked as iron deficiency (even without anemia) can contribute to fatigue, poor concentration, and mood disturbances 1

Metabolic Panel

• Comprehensive metabolic panel to assess glucose, electrolytes, kidney and liver function 1
• Hypoglycemia or electrolyte imbalances can present with anxiety-like symptoms 1

Nutritional Deficiencies

• Vitamin D 25-OH should be measured, as deficiency is associated with mood disorders and anxiety 1
• Vitamin B12 deficiency can cause neuropsychiatric symptoms including anxiety, cognitive impairment, and obsessive thoughts 1
• Folate (erythrocyte folate) may be considered as deficiency can contribute to mood and anxiety symptoms 1

Additional Considerations Based on Clinical Context

If History of Gestational Diabetes

• Fasting glucose or HbA1c should be ordered if the patient had gestational diabetes, as she should be screened for persistent diabetes or prediabetes at 4-12 weeks postpartum using a 75-g oral glucose tolerance test 1
• This is particularly relevant as undiagnosed diabetes can present with anxiety and cognitive symptoms 1

If Breastfeeding

• Albumin/total protein and transthyretin (prealbumin) may be considered to assess nutritional status, especially if dietary intake is restricted or inadequate 1

Clinical Pitfalls to Avoid

Don't Assume It's "Just Postpartum"

• While postpartum anxiety and OCD are common psychiatric conditions, medical causes must be ruled out first 2, 3
• Untreated medical conditions can worsen psychiatric symptoms and interfere with treatment response 3

Distinguish from Normal Postpartum Concerns

• Normal postpartum checking behaviors differ from OCD in that OCD symptoms are time-consuming (>1 hour daily), cause significant distress, and impair functioning 1
• Screening should be performed even when symptoms overlap with normal concerns, as undiagnosed OCD has adverse consequences for mother and infant 3

Consider Comorbid ADHD

• If the patient reports significant difficulty with concentration, organization, or "brain fog," screen for ADHD using the Adult ADHD Self-Report Scale (ASRS-V1.1), as ADHD symptoms commonly worsen postpartum and can coexist with anxiety 4, 5
• Rule out other conditions that may mimic psychiatric symptoms including sleep disorders and nutritional deficiencies 4

Rationale for This Approach

The laboratory workup prioritizes identifying treatable medical conditions that can present with or exacerbate anxiety and OCD symptoms 3. Thyroid dysfunction, anemia, vitamin deficiencies, and metabolic abnormalities are all common in the postpartum period and can significantly impact mental health 1. Addressing these medical factors first optimizes the response to psychiatric treatment and prevents misattribution of medical symptoms to psychiatric illness alone 3.