Are these blood results consistent with Polycystic Ovary Syndrome (PCOS) and what is the impact on ovulatory function?

Analysis of Blood Results for PCOS and Ovulatory Function

Cannot Definitively Assess PCOS or Ovulatory Function with Current Hormonal Contraception

Your blood results cannot be reliably interpreted for PCOS diagnosis while the Implanon (etonogestrel implant) is in place, as the progestin suppresses the hypothalamic-pituitary-ovarian axis and makes hormone levels unreliable for diagnosing PCOS. 1

Why These Results Are Uninterpretable

The progestin-only implant fundamentally alters the hormonal landscape needed for PCOS diagnosis:

• LH/FSH ratio becomes meaningless: Progestin suppression of gonadotropin secretion eliminates the characteristic elevated LH or elevated LH/FSH ratio (>2) seen in many PCOS patients 1, 2
• Testosterone interpretation is compromised: While total testosterone via LC-MS/MS is the best single biochemical marker for PCOS (74% sensitivity, 86% specificity), progestin-induced changes in SHBG and suppressed ovarian function alter the hormonal context 1
• Ovulatory function cannot be assessed: The implant is designed to suppress ovulation, so any assessment of natural ovulatory function is impossible while it remains in place 1

What Your Ultrasound Shows: Not PCOS

Your ovarian volumes actually argue against PCOS:

• Right ovary: 4.56cc - This is normal and well below the PCOS threshold 3, 4
• Left ovary: 1.05cc - This is concerningly small, suggesting diminished ovarian reserve rather than PCOS 3, 4

PCOS requires ovarian volume >10 mL (10cc) in at least one ovary, and neither of your ovaries meets this criterion. 3, 1 The diagnostic threshold for polycystic ovarian morphology is ≥20 follicles (2-9mm diameter) per ovary OR ovarian volume >10mL using transvaginal ultrasound with ≥8 MHz transducer frequency 3, 1

Primary Concern: Diminished Ovarian Reserve

Your left ovary volume of 1.05cc is below the 3 cm³ threshold that suggests diminished ovarian reserve, which is a concerning finding requiring additional workup. 3, 4

When ovarian volume is <3 cm³ and <5 antral follicles are present, this suggests diminished ovarian reserve 3, 4. The combination of irregular periods with a small ovary volume raises concern for premature ovarian insufficiency (POI) or primary ovarian failure, particularly if you are under 40 years old 4.

Required Next Steps for Accurate Assessment

To properly evaluate for PCOS and ovulatory function, you must:

1. Remove the Implanon or wait for it to expire before hormonal testing 1

2. Wait 2-3 months after removal to allow your natural hormonal axis to recover before testing 1

3. Then obtain proper diagnostic testing:

   • Total testosterone via LC-MS/MS (not immunoassay) 1, 2
   • Calculated free testosterone using the Vermeulen equation 1, 2
   • LH and FSH measured between cycle days 3-6 2
   • Mid-luteal progesterone to confirm ovulation (levels <6 nmol/L indicate anovulation) 2
   • TSH to rule out thyroid disease 2
   • Prolactin (morning resting levels) to exclude hyperprolactinemia 2
   • AMH level (though not diagnostic alone, <35 pmol/L would support diminished ovarian reserve) 1, 4
   • Antral follicle count on ultrasound (<5 antral follicles combined with low ovarian volume strongly suggests diminished reserve) 3, 4

4. Metabolic screening regardless of PCOS diagnosis:

   • Two-hour oral glucose tolerance test with 75g glucose load 2
   • Fasting lipid panel 2

Clinical Pitfalls to Avoid

• Do not dismiss the small left ovary as insignificant asymmetry - this degree of volume discrepancy warrants investigation for unilateral ovarian pathology or systemic ovarian dysfunction 4
• Do not pursue PCOS workup when ovarian volumes are normal and clinical hyperandrogenism is absent - this leads to misdiagnosis and inappropriate treatment 4
• Do not rely on AMH alone for diagnosis - AMH levels are elevated in PCOS but not yet recommended for clinical diagnosis due to lack of standardization and established cut-offs 3, 1

Can PCOS Be Diagnosed Without Abnormal Labs?

Yes, but only with the right clinical picture. A woman can be diagnosed with PCOS based solely on clinical hyperandrogenism (hirsutism, acne, or alopecia) plus irregular menstrual cycles, without any abnormal laboratory values, according to the Rotterdam criteria. 2 However, this requires documented clinical hyperandrogenism and menstrual irregularity that persists off hormonal contraception 1, 2.

Total testosterone is abnormal in only 70% of women with confirmed PCOS, meaning 30% have normal testosterone levels despite having the condition 2. The LH/FSH ratio >2 is abnormal in only 35-44% of women with PCOS, making it a poor diagnostic marker 2.

Bottom Line

Your current blood work cannot confirm or exclude PCOS while on Implanon, and your ultrasound findings suggest diminished ovarian reserve rather than PCOS. 1, 4 Remove the implant, wait 2-3 months, then obtain comprehensive hormonal testing to properly assess both PCOS and ovulatory function 1. The small left ovary requires specific attention and may indicate a more significant reproductive health concern than PCOS 3, 4.