Progesterone Levels After Embryo Transfer: What Is a Good Number?

What Is Progesterone and Why Does It Matter After Transfer?

The hormone responsible for making the uterine lining ready to receive the fertilized egg is progesterone. Post ovulation (or trigger injection in IVF), the corpus luteum (egg follicle remnant) creates progesterone. During early pregnancy, progesterone maintains the lining thick and inhibits menstruation. Too little progesterone results in the lining coming away and a pregnancy loss.

Progesterone Levels: Timing and Interpretation

Progesterone is measured via blood test, typically 7–8 days after ovulation (or trigger injection). Normal ranges:

• - Follicular phase (before ovulation): <1 ng/mL
• - Post-ovulation/luteal phase: typically 5–20 ng/mL, with most studies considering >10 ng/mL 'normal'
• - In IVF with progesterone supplementation: levels can be 20–50+ ng/mL (higher than natural because you're taking external hormones)

What Constitutes 'Low' Progesterone?

This is debated. Studies show:

• - Progesterone <10 ng/mL in natural cycles may indicate poor corpus luteum function
• - Progesterone <5 ng/mL despite supplementation suggests inadequate absorptionBUT: even low levels can support viable pregnancies if you're taking supplemental progesterone (injections or pessaries are reliable)
• - ALSO: if you are taking vaginal pessaries or gel, the absorption of progesterone is local from the vaginal mucosa to the uterine lining. It shows low levels in a blood test, but there is enough progesterone in the uterine lining, where the action is actually needed. So, if you are not on injections for progesterone, checking and judging blood progesterone levels may not be advised. 

Why You're Taking Progesterone Supplementation

In IVF, you receive progesterone supplementation because:

• - Egg retrieval disrupts the corpus luteum (the cells that are needed to generate progesterone are removed along with the egg)
• - Natural progesterone production after retrieval is unreliable
• - Supplementation guarantees adequate progesterone, regardless of your body's production

Whether your blood progesterone is 10 or 50 ng/mL, if you're taking prescribed supplementation, you're covered. The supplement's progesterone is in your bloodstream.

Progesterone Testing During Pregnancy

In early pregnancy, progesterone continues to rise. Testing every 48 hours is unnecessary and causes anxiety. Most clinics may not test or test once or twice in the first week, then stop. A single number doesn't predict viability; trends over 48–72 hours (with hCG) are more informative.

Q: What if my progesterone is 25 ng/mL on day 7—is that 'too high'?

A: No. With supplementation, levels of 20–50+ are normal and expected. Higher isn't harmful.

Q: If my natural progesterone is low without supplementation, will IVF fail?

A: Not if you're taking supplements. That's the point of supplementation—to overcome low natural production.