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Progesterone

Fertility profile Biomarker

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Collection Type: Blood

Body System

Related System: Fertility profile

Overview

Progesterone is a steroid hormone produced mainly by the corpus luteum after ovulation and by the placenta during pregnancy; small amounts are also made by the adrenal glands and testes. The blood test measures circulating progesterone to assess whether ovulation has occurred, to evaluate luteal phase adequacy, and to monitor early pregnancy viability or luteal support during fertility treatment. Abnormal levels can point to anovulation, luteal phase defect, ovarian or adrenal disorders, or pregnancy problems (threatened miscarriage, ectopic). Results vary widely by sex, menstrual-cycle phase, menopausal status and pregnancy: reproductive-age women show marked cyclical changes, postmenopausal women and men have low baseline levels, and pregnant women have progressively higher values.

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Test Preparation

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Why Do I Need This Test

Profile: Fertility profile (also used in early pregnancy monitoring and endocrine evaluation) - Symptoms prompting test: irregular or absent periods, infertility, abnormal bleeding, recurrent pregnancy loss, suspected miscarriage/ectopic pregnancy - Conditions diagnosed/monitored: ovulation confirmation, luteal phase deficiency, early pregnancy health, effects of progesterone therapy - Reasons for abnormal levels: anovulation, ovarian failure, adrenal disorders, pregnancy, exogenous progesterone, ovarian tumors - Biological meaning: low levels indicate absent or inadequate corpus luteum function; high levels reflect luteal activity, pregnancy, or exogenous/tumor sources - Lifestyle factors: obesity, extreme exercise, stress, certain medications (hormonal contraceptives, glucocorticoids) can alter levels - Family history: recurrent early pregnancy loss, known endocrine disorders, or familial ovarian/adrenal tumor syndromes may prompt testing

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Understanding Test Results

Values must be interpreted relative to cycle timing.
Follicular-phase values (about 0.1–0.8 ng/mL) are low and normal before ovulation.
A rise to ~0.8–3.0 ng/mL around ovulation indicates the ovulatory surge; many clinicians use a single serum progesterone >3 ng/mL (some prefer >5 ng/mL) in the mid‑luteal sample to confirm that ovulation has occurred.
Mid‑luteal concentrations are typically 5–20+ ng/mL; persistently low mid‑luteal values (<3–5 ng/mL) suggest anovulation or luteal phase deficiency and are associated with infertility or menstrual irregularity.
In early pregnancy, progesterone usually rises (commonly into double digits ng/mL); levels persistently low in early pregnancy (often cited <10–20 ng/mL) are associated with a higher risk of miscarriage or failing pregnancy.
Very high values are expected with established pregnancy or with exogenous progesterone therapy; markedly elevated levels outside pregnancy may prompt evaluation for ovarian or adrenal pathology.
Interpretation should consider timing, symptoms, medications, and repeat measurements when needed.

Normal Range

Follicular phase: 0.1–0.8 ng/mL OR 0.32–2.55 nmol/L; Ovulation (peak): 0.8–3.0 ng/mL OR 2.55–9.54 nmol/L; Mid‑luteal phase: 1.8–24.0 ng/mL OR 5.72–76.3 nmol/L; Early pregnancy (1st trimester typical): 11–90 ng/mL OR 35–286 nmol/L; Postmenopausal: <0.5 ng/mL OR <1.6 nmol/L

FAQs

Q: What does progesterone do in the body?

A: Progesterone is a steroid hormone produced mainly by the ovaries, placenta and adrenal glands. It regulates the menstrual cycle and prepares and maintains the uterine lining for implantation and early pregnancy, reduces uterine contractions, and supports breast changes for lactation. Progesterone also influences mood, raises basal body temperature, contributes to bone health, and interacts with estrogen to balance reproductive and metabolic functions.

Q: What happens if progesterone is low?

A: Low progesterone can cause irregular or absent periods, a short luteal phase and difficulty conceiving. It may lead to early pregnancy loss, spotting and unpredictable bleeding because the uterine lining isn’t maintained. Women may also experience mood swings, insomnia, decreased libido and hot flashes. Long-term deficiency can contribute to bone loss and, if unopposed by estrogen, increased risk of endometrial overgrowth.

Q: What happens when a woman starts taking progesterone?

A: When a woman starts progesterone (or a progestogen), it prepares and uterine lining, can change or stop bleeding, may suppress ovulation while used, raises basal body temperature, and helps maintain early pregnancy. Common side effects include breast tenderness, bloating, mood changes, fatigue, spotting, headaches and altered libido. It’s used for cycle regulation, contraception, treating heavy bleeding, and hormone therapy.

Q: What happens if progesterone is high?

A: High progesterone—seen in pregnancy, the luteal phase, supplements or hormone‑secreting tumors—can cause fatigue, mood changes, breast tenderness, bloating, constipation, headaches, dizziness, reduced libido and sleepiness. It may alter menstrual bleeding (irregularity or amenorrhea), cause fluid retention/weight gain, and in men contribute to sexual dysfunction. Very high levels warrant medical evaluation to exclude endocrine disorders or medication effects.

Q: Does progesterone cause weight gain?

A: Progesterone can cause modest weight changes, mainly from fluid retention, bloating, and sometimes increased appetite. Some synthetic progestins are more likely to be linked with weight gain than micronized progesterone. Significant long‑term fat gain from progesterone alone is uncommon effects vary by dose, formulation, duration, and individual factors. Discuss concerns and alternatives with your clinician.

Q: How does progesterone make a woman feel?

A: Progesterone can make women feel more tired, sleepy and relaxed, and sometimes calmer or emotionally sensitive. It commonly causes mood swings, irritability, anxiety or low mood, plus breast tenderness, bloating, headaches, dizziness and reduced libido. Cognitive fog or difficulty concentrating can occur. Effects vary with dose, cycle phase or hormone therapy.