🌙 Progesterone
A key hormone that helps regulate the menstrual cycle, supports pregnancy, and confirms ovulation.

🔍 What is it?

Progesterone is a hormone mainly produced by the ovaries after ovulation. It plays a vital role in preparing the uterus for pregnancy, regulating the menstrual cycle, and supporting early pregnancy.

Levels naturally rise after ovulation and fall if pregnancy doesn’t occur — which helps trigger your period.

🧪 What does it measure?

• Progesterone (Day 21 Test) –
  Measures how much progesterone is in your blood, typically done around day 21 of a 28-day cycle (7 days after ovulation).
  Helps determine if ovulation has occurred.

❓ Why might I need it?

You may be advised to take this test if you:

• 🍼 Are trying to conceive and want to confirm ovulation
• 🔁 Have irregular cycles or missed periods
• 🩸 Have heavy or abnormal bleeding
• 🤰 Want to assess progesterone support during early pregnancy
• 🔬 Are being treated for infertility
• 🧓 Suspect hormone imbalance or luteal phase defect

🧬 Conditions it can help detect or monitor:

• Ovulation status – confirms if ovulation is occurring
• Luteal phase defects – low progesterone post-ovulation
• Miscarriage risk – especially in early pregnancy
• Menstrual irregularities
• Infertility investigations

🩺 How is it done?

• 💉 A simple blood test
• 📅 Typically done 7 days before your expected period (e.g. Day 21 in a 28-day cycle)
• ⏱️ Results in 1–3 working days

💷 Typical Private Cost in the UK:

£40–£85
Often included in fertility or hormone panels

✅ Commonly Combined With:

• FSH & LH – to assess full ovulatory function
• Oestradiol (Estrogen) – to evaluate hormonal balance
• AMH (Anti-Müllerian Hormone) – to check ovarian reserve
• Thyroid tests (TSH, T3, T4) – thyroid issues can affect ovulation
• Prolactin – to check for other hormone disruptions

📚 References:

• NHS – [Progesterone blood test and fertility]
• NICE – [Fertility: assessment and treatment]
• Royal College of Obstetricians and Gynaecologists (RCOG)