Ovulation Assessment in a 37-Year-Old Female
Direct Answer
This patient has not ovulated based on her progesterone level of 2 nmol/L, which falls well below the 6 nmol/L threshold required to indicate possible ovulation. 1
Interpretation of Hormone Profile
Progesterone: The Definitive Marker
- Progesterone <6 nmol/L is not indicative of ovulation, and this patient's level of 2 nmol/L confirms anovulation for this cycle 1
- The American College of Obstetricians and Gynecologists states that progesterone measurement is the gold standard for confirming ovulation, with a threshold of ≥16 nmol/L (≥5 ng/mL) typically indicating confirmed ovulation 1
- Mid-luteal progesterone measurement (approximately 7 days post-ovulation) is the most reliable confirmatory test, where levels <6 nmol/L indicate anovulation 1
FSH and LH Levels: Context Matters
- FSH of 7.3 U/L falls within the normal follicular phase range (3-10 U/L) and does not suggest ovarian reserve problems 1
- LH of 8.1 U/L is slightly elevated above the follicular phase range (2-8 U/L) but remains within mid-cycle parameters (10-75 U/L) 1
- The LH level could represent either an LH surge that failed to trigger ovulation or a baseline elevation seen in conditions like PCOS 2
Oestradiol Levels
- Oestradiol of 127 pmol/L falls within the follicular phase range (50-850 pmol/L), suggesting some follicular activity is occurring 1
- This level is too low for mid-cycle (150-1450 pmol/L), confirming the absence of a mature preovulatory follicle 1
Critical Timing Consideration
The "day 21" progesterone test assumes a 28-day cycle with ovulation on day 14. 1 For women with irregular cycles, testing should be performed approximately 7 days before expected menses (mid-luteal phase) 1. If this patient has irregular cycles, the timing of this blood draw may have been inappropriate, potentially missing the actual luteal phase.
Clinical Implications and Next Steps
Immediate Assessment
- Repeat progesterone testing timed to 7 days post-ovulation (approximately cycle day 21-22 for a 28-day cycle) to confirm robust luteal function 1
- Consider urinary LH testing to detect the LH surge, which precedes ovulation by 24-36 hours, to better time progesterone measurement 1
- Track basal body temperature, which should show a sustained thermal shift if ovulation occurs 1
Evaluation for Anovulation Causes
- Assess for polycystic ovary syndrome (PCOS), particularly given the slightly elevated LH, which could represent the elevated LH:FSH ratio (>2) characteristic of PCOS 3
- Evaluate thyroid function, as thyroid disorders commonly affect reproductive hormones and can cause anovulation 1
- Check prolactin levels to exclude hyperprolactinemia, which can disrupt ovulation 1
- Assess body mass index and nutritional status, as both underweight (BMI <18.5) and obesity can suppress ovulation 3
Common Pitfalls to Avoid
- Do not assume ovulation occurred based on FSH and LH levels alone—only progesterone confirms ovulation 1
- Medications, particularly hormonal contraceptives, can suppress normal hormone patterns and affect progesterone levels 1
- A single hormone measurement may be misleading due to the pulsatile nature of gonadotropin secretion 4
Likelihood Assessment
The likelihood of ovulation in this cycle is essentially zero based on the progesterone level of 2 nmol/L 1. However, the presence of normal FSH and some follicular activity (evidenced by oestradiol of 127 pmol/L) suggests the ovaries retain functional capacity and ovulation may occur in other cycles with appropriate intervention or spontaneously 1, 5.