What is the normal progesterone level for a 33-year-old woman?

Normal Progesterone Levels for a 33-Year-Old Woman

Progesterone levels in a 33-year-old woman vary dramatically throughout the menstrual cycle, ranging from <1 ng/mL (approximately 0.65 ng/mL or 2 nmol/L) during the follicular phase to 10-25 ng/mL (approximately 12.4 ng/mL or 32-80 nmol/L) during the mid-luteal phase. 1, 2, 3

Follicular Phase (Days 1-14)

• Baseline progesterone: 0.65 ± 0.12 ng/mL (approximately 2 nmol/L) 2
• Essentially no ovarian progesterone secretion occurs during this phase 4
• Levels remain low and stable, similar to male baseline levels (18-21 ng/dL) 4

Ovulation/LH Peak (Day 14)

• Progesterone begins to rise as the corpus luteum forms 3
• Levels transition from follicular to luteal phase values 2

Luteal Phase (Days 15-28)

Early Luteal Phase (Days 15-18)

• Progesterone rises rapidly after ovulation 3
• Levels begin climbing toward mid-luteal peak 2

Mid-Luteal Phase (Days 19-23)

• Peak progesterone: 12.4 ± 2.3 ng/mL (approximately 32-80 nmol/L) 2, 3
• This represents a 10-15 fold increase over follicular phase levels 2
• Clinical threshold for ovulation confirmation: >6 nmol/L (approximately 1.9 ng/mL) indicates ovulation occurred 1
• Optimal diagnostic timing: Days 25-26 of the cycle, with discriminatory level of 21 nmol/L (approximately 6.6 ng/mL) for luteal phase adequacy 5

Late Luteal Phase (Days 24-28)

• In non-pregnant cycles, progesterone drops back toward baseline 6
• In conception cycles, progesterone remains elevated above mid-luteal values 6
• Late luteal rise in estradiol is more sensitive for pregnancy detection than progesterone rise 6

Key Clinical Thresholds

For ovulation assessment 1:

• <6 nmol/L (1.9 ng/mL): Indicates anovulation

• 6 nmol/L (1.9 ng/mL): Confirms ovulation occurred

For luteal phase adequacy 5:

• <21 nmol/L (6.6 ng/mL) on days 25-26: Suggests luteal phase deficiency (sensitivity 81%, specificity 73%)
• ≥21 nmol/L (6.6 ng/mL) on days 25-26: Normal luteal function

Important Clinical Caveats

• Timing is critical: Blood must be drawn during the mid-luteal phase (approximately 7 days after ovulation or days 19-23 of a 28-day cycle) for meaningful interpretation 1, 5
• Single measurements are limited: Wide inter-cycle and inter-individual variation exists, making single values difficult to interpret without cycle phase context 3
• Age-specific considerations: For women aged 30-39, DHEAS reference ranges differ (>2700 ng/mL considered elevated), though this primarily affects androgen assessment rather than progesterone interpretation 1
• Progesterone levels are NOT routinely used to guide supplementation decisions in pregnancy: Current guidelines base progesterone supplementation on clinical risk factors (prior preterm birth, short cervix), not serum progesterone values 7, 8