Normal LH, FSH, and Estradiol in Reproductive-Age Females
Normal LH, FSH, and estradiol levels in a reproductive-age female indicate intact hypothalamic-pituitary-ovarian axis function with adequate ovarian reserve and suggest regular ovulatory cycles when measured during the early follicular phase (days 3-6). 1, 2
What Normal Values Mean
Baseline hormone assessment (days 3-6):
- Normal FSH and LH levels measured during the early follicular phase indicate adequate ovarian reserve and responsiveness to gonadotropin stimulation 1, 2
- The most accurate assessment requires averaging three blood draws taken 20 minutes apart during cycle days 3-6 1, 3
- Normal estradiol during this phase confirms follicular activity and ovarian steroidogenic capacity 1, 3
Implications for ovulatory function:
- To confirm actual ovulation (not just normal baseline hormones), mid-luteal progesterone measurement is essential—levels ≥6 nmol/L indicate ovulation occurred 1, 2
- Normal baseline hormones do NOT guarantee ovulation; anovulation can occur despite normal FSH, LH, and estradiol if measured only in the follicular phase 1
Age-Related Context
Younger reproductive years (20s-30s):
- FSH typically ranges 3-7 IU/L during early follicular phase 4
- LH ranges approximately 1.1-4.2 IU/L 5
- These values indicate robust ovarian reserve and high fertility potential 4
Late reproductive years (40s):
- FSH begins rising significantly after age 39, potentially reaching 4-32 IU/L while still maintaining regular cycles 5, 6
- Estradiol may show transient fluctuations but generally remains in fertile range 6
- Normal values in this age group still suggest ongoing ovarian function but with declining reserve 5
Critical Pitfalls to Avoid
Timing errors render results uninterpretable:
- Measurements must occur on cycle days 3-6 specifically; testing at other times cannot assess baseline ovarian function 1, 2
- Hormonal contraceptives must be discontinued at least 2 months before testing to allow return of normal pituitary-ovarian axis function 1, 2
Normal baseline hormones don't exclude reproductive disorders:
- Women with polycystic ovary syndrome (PCOS) may show normal FSH and estradiol but have LH/FSH ratio >2, indicating anovulation despite seemingly normal individual values 1, 3
- Luteal phase defects causing infertility will not be detected by follicular phase testing alone 1
Single measurements can be misleading:
- FSH can fluctuate dramatically during the menopausal transition—even postmenopausal-range FSH may be followed by ovulatory cycles 7
- For women with irregular cycles, anti-Müllerian hormone (AMH) provides more stable assessment as it doesn't vary by cycle day 2, 3
When Normal Values Require Further Investigation
Despite normal hormones, evaluate further if:
- Menstrual irregularity persists (cycles <23 or >35 days) 1
- Infertility after 12 months of unprotected intercourse 1
- Clinical signs suggest endocrine disorder (hirsutism, galactorrhea, significant weight changes) 1
Additional testing needed: