What hormone labs should be run for a patient with Polycystic Ovary Syndrome (PCOS) who has been using an Intrauterine Device (IUD) for 2 years and presents with new irregular spotting?

Hormone Labs for PCOS Patient with IUD and New Irregular Spotting

The priority is to first rule out pregnancy and IUD-related complications before attributing spotting to PCOS hormonal changes, then selectively test hormones only if clinically indicated based on your evaluation.

Initial Essential Testing

Pregnancy test is mandatory as the first step when any woman with an IUD develops new-onset bleeding, regardless of PCOS status 1, 2. This addresses the most critical safety concern.

IUD-Specific Evaluation (Before Hormone Testing)

Before ordering hormone panels, you must:

• Check for IUD displacement by verifying string presence on pelvic exam, as displacement commonly causes abnormal bleeding 1, 2
• Screen for sexually transmitted infections and pelvic inflammatory disease, which are common causes of new-onset bleeding in IUD users 1, 2
• Assess for new pathologic uterine conditions such as polyps or fibroids that may have developed during the 2 years of IUD use 1, 2

Important caveat: The Centers for Disease Control and Prevention explicitly warns against automatically attributing new bleeding to other factors (including hormonal changes from PCOS) without first investigating IUD-related and gynecologic causes 1. New-onset spotting after a period of stable bleeding warrants thorough evaluation 2.

Hormone Testing: When and What to Order

If IUD evaluation is normal and clinical suspicion exists for PCOS progression or other endocrine issues:

• Total testosterone is the single best hormonal marker, abnormal in 70% of PCOS cases 3
• Free testosterone (ideally by equilibrium dialysis) is more sensitive than total testosterone for detecting androgen excess 4
• LH and FSH measured in early follicular phase, though these are elevated in only 35% of PCOS cases 3
• TSH to screen for thyroid dysfunction, which is a predictor of PCOS and metabolic abnormalities 5
• Prolactin as elevated levels are associated with PCOS and can cause menstrual irregularities 5

Hormones with limited utility in this scenario:

• LH/FSH ratio should NOT be routinely ordered - it has low sensitivity (abnormal in only 41-44% of PCOS cases) and should be abandoned as a diagnostic criterion 3
• Androstenedione is abnormal in 53% of cases but adds limited value beyond testosterone 3
• DHEA-S shows no significant difference between PCOS and controls 3
• AMH should NOT be used as a single test for PCOS diagnosis per international guidelines 6
• 17-hydroxyprogesterone is useful for PCOS diagnosis but primarily to exclude non-classic congenital adrenal hyperplasia 4

Clinical Decision Algorithm

1. Immediate: Urine pregnancy test
2. Same visit: Pelvic exam to check IUD strings and assess for displacement
3. If strings not visible or displaced: Pelvic ultrasound to locate IUD
4. If IUD properly positioned: STI screening (gonorrhea, chlamydia)
5. If infection ruled out: Pelvic ultrasound to evaluate for polyps, fibroids, or endometrial pathology 1
6. Only after above are negative: Consider selective hormone testing based on clinical presentation:
   • If signs of worsening hyperandrogenism (new hirsutism, acne): Total and free testosterone 4, 3
   • If menstrual pattern suggests anovulation beyond IUD effects: LH, FSH (early follicular phase timing) 5
   • If metabolic concerns or weight changes: TSH, consider fasting glucose and lipids 5, 7
   • If galactorrhea or other prolactin-related symptoms: Prolactin 5

Key Clinical Pitfalls to Avoid

• Do not remove the IUD without investigating underlying causes first 2
• Do not assume the IUD is "wearing off" at 2 years when other pathology is more likely 2
• Do not order comprehensive hormone panels reflexively - the spotting is more likely IUD-related than PCOS-related after 2 years of stable use 1, 2
• Reassure the patient that if no underlying problem is identified, bleeding irregularities with levonorgestrel IUDs are generally not harmful 1, 2

Expected Bleeding Patterns Context

Levonorgestrel IUDs typically cause spotting in the first 3-6 months, with bleeding decreasing over time 1, 2. By 2 years, approximately half of users experience amenorrhea or oligomenorrhea 1, 2. New-onset spotting after 2 years of stable patterns is abnormal and requires investigation rather than being dismissed as normal IUD effects 2.