What labs are recommended to assess female hormone deficiency?

Laboratory Assessment for Female Hormone Deficiency

Measure FSH and LH on cycle days 3-6 (ideally averaged from three samples taken 20 minutes apart), mid-luteal progesterone, estradiol, TSH, and prolactin as your core hormone panel. 1

Core Hormone Panel

FSH and LH (Days 3-6 of Cycle)

• Draw between cycle days 3-6 to capture baseline gonadotropin levels before follicular recruitment begins 2, 1
• For maximum accuracy, calculate the average of three blood draws taken 20 minutes apart 2, 1
• FSH >35 IU/L and LH >11 IU/L indicate ovarian failure (hypergonadotropic hypogonadism) 2, 1
• LH/FSH ratio >2 suggests polycystic ovary syndrome (PCOS) and likely anovulation 2, 1
• LH <7 IU/mL may indicate hypothalamic dysfunction 2, 1
• FSH on days 1-2 is the best single predictor of ovarian reserve when comparing reproductive age groups 3

Progesterone (Mid-Luteal Phase)

• Progesterone <6 nmol/L indicates anovulation and is the most reliable hormonal indicator of ovulation 2, 1
• Blood must be drawn during mid-luteal phase according to the menstrual cycle 2

Estradiol (Days 3-6 of Cycle)

• Measure on days 3-6 alongside FSH/LH as it is essential for assessing ovarian function 1
• Low estradiol with elevated FSH confirms ovarian insufficiency 1
• Normal to high estradiol with elevated LH/FSH ratio supports PCOS diagnosis 1

TSH

• TSH is essential as thyroid dysfunction commonly causes menstrual irregularity and must be excluded 2, 1

Prolactin

• Measure in morning resting samples (not postictal) 2, 1
• Prolactin >20 μg/L is abnormal and warrants investigation for hypothyroidism or pituitary tumor 2, 1

Additional Testing Based on Clinical Context

Testosterone and Androgens (Days 3-6)

• Testosterone >2.5 nmol/L suggests PCOS or valproate effect 2
• Androstenedione >10.0 nmol/L requires exclusion of adrenal/ovarian tumor 2
• DHEAS elevation (age 20-29: >3800 ng/mL; age 30-39: >2700 ng/mL) suggests non-classical congenital adrenal hyperplasia 2

Glucose and Insulin

• Fasting glucose >7.8 mmol/L suggests diabetes 2
• Glucose/insulin ratio >4 suggests reduced insulin sensitivity associated with obesity and PCOS 2

Anti-Müllerian Hormone (AMH)

• For women with irregular or absent cycles, AMH does not vary by menstrual day and is not affected by exogenous estrogen or progesterone 1
• Interpret with caution in women under age 25 due to significant fluctuations 1

Critical Pitfalls to Avoid

• Wrong cycle phase timing renders results uninterpretable 1
• Discontinue hormonal contraceptives at least 2 months before testing as they suppress normal FSH and LH patterns 1
• Antiepileptic drugs can impact hormone levels and cause reproductive endocrine disorders 2, 1
• Prolactin should never be measured postictal as it will be spuriously elevated 2

Pattern Recognition for Diagnosis

PCOS Pattern

• LH/FSH ratio >2, elevated LH throughout cycle, normal to high estradiol 1
• Low mid-luteal progesterone indicating anovulation 2, 1

Functional Hypothalamic Amenorrhea Pattern

• Low gonadotropins, LH/FSH ratio <1, low estradiol with thin endometrium 1

Ovarian Failure Pattern

• FSH >35 IU/L, LH >11 IU/L, low estradiol 2, 1

When to Refer to Endocrinology/Gynecology

• Prepubertal females with no signs of puberty by age 13 years 1
• Primary amenorrhea by age 16 years 1
• Postpubertal females with menstrual cycle dysfunction suggestive of premature ovarian insufficiency 1
• Any patient diagnosed with ovarian insufficiency requiring sex steroid replacement therapy consideration 1