Normal Hormone Reference Ranges for a 30-Year-Old Female
The normal reference ranges for these hormones in a 30-year-old woman vary by assay and clinical context, but standardized values can guide interpretation, with particular attention needed for menstrual cycle phase and oral contraceptive use.
Key Hormones with Established Reference Ranges
Thyroid-Stimulating Hormone (TSH)
- Normal range: 0.45-4.5 mIU/L 1
- This represents the statistically defined reference range from rigorously screened populations 1
- Some controversy exists regarding whether the upper limit should be 2.5 mIU/L, but no evidence supports adverse consequences for values between 2.5-4.5 mIU/L in asymptomatic individuals 1
Adrenocorticotropic Hormone (ACTH)
- Morning (8-9 AM) range: >5 ng/L (>1.1 pmol/L) is detectable/normal 1
- Values >29 ng/L (6.4 pmol/L) have 70% sensitivity and 100% specificity for diagnosing ACTH-dependent conditions 1
- Important caveat: ACTH must be drawn in the morning (8-9 AM) for accurate interpretation 1
- ACTH levels can be suppressed by oral contraceptive use 2
Follicle-Stimulating Hormone (FSH)
- Reproductive age women: 3-7 IU/g creatinine (urinary) or approximately 3-20 mIU/mL (serum, varies by cycle phase) 3
- FSH varies significantly throughout the menstrual cycle 1
- Follicular phase values are typically lower than luteal phase 3
- Perimenopausal women show elevated FSH (4-32 IU/g Cr) compared to younger reproductive-age women 3
Luteinizing Hormone (LH)
- Reproductive age women: 1.1-4.2 IU/g creatinine (urinary) or approximately 5-25 mIU/mL (serum, varies by cycle phase) 3
- LH shows marked variation with menstrual cycle phase, with mid-cycle surge preceding ovulation by 24-36 hours 4
- Oral contraceptives significantly suppress LH levels 2
Prolactin
- Normal range: Typically <25 ng/mL in non-pregnant women (based on general medical knowledge, as specific ranges not provided in evidence)
- Should be measured as part of pituitary axis evaluation 1
Hormones Without Well-Established Standard Ranges
Growth Hormone (GH)
- GH secretion is pulsatile, making random measurements unreliable for assessment 5
- Stimulation testing (insulin tolerance test or glucagon stimulation test) is required to evaluate GH deficiency 5
- No single reference range exists for random GH levels due to episodic secretion patterns
Antidiuretic Hormone (ADH/Vasopressin)
- No standard reference ranges provided in clinical guidelines
- ADH is typically assessed functionally through serum and urine osmolality rather than direct measurement
- Diabetes insipidus evaluation requires specialized testing beyond simple hormone measurement 1
Oxytocin
- No established clinical reference ranges for routine use
- Not part of standard pituitary axis evaluation 1
Critical Clinical Considerations
Menstrual Cycle Phase Matters
- FSH, LH, estrogen, and progesterone vary dramatically throughout the cycle 3, 2
- Day 21 progesterone ≥5 ng/mL (≥16 nmol/L) confirms ovulation in a 28-day cycle 4
- For irregular cycles, timing should be adjusted to approximately 7 days before expected menses 4
Oral Contraceptive Effects
- Oral contraceptives significantly suppress LH, FSH, estradiol, and progesterone 2
- ACTH levels are lower while cortisol levels are paradoxically higher in women on oral contraceptives 2
- Separate reference limits may be necessary for women on estrogen-containing contraceptives 6
Assay-Specific Variations
- Cortisol responses to ACTH stimulation are highly method-specific, with different lower reference limits for each immunoassay platform 6
- Heterophilic antibodies can cause falsely elevated TSH in some assays 1