The luteal phase is the part of your cycle from ovulation to the day before your next period. It usually lasts 11 to 17 days, most often around 14, and stays fairly stable from cycle to cycle for the same person. Differences in total cycle length mostly come from the phase before ovulation, not this one. A luteal phase shorter than 10 days is considered short.
What happens in the luteal phase
After ovulation, the empty follicle becomes the corpus luteum, which produces progesterone. Progesterone thickens the lining of the uterus, raises basal body temperature and thickens cervical mucus. If an embryo does not implant, the corpus luteum stops working after about two weeks, hormones fall and your period starts. Read more on our luteal phase page.
How to measure your luteal phase
You need to know when you ovulated. Two common ways:
- Basal body temperature: count from the first day of the sustained rise until the day before your next period.
- LH tests: ovulation usually happens one to two days after a positive test; count from the day after ovulation until the day before your period.
Measure over at least two or three cycles. Cervical mucus helps you narrow down the day.
| Luteal phase | What it usually means |
|---|---|
| 11 to 17 days | Within the typical range |
| 10 days or fewer | Short; worth discussing if it repeats |
| No clear ovulation found | Possibly a cycle without ovulation, or not enough data |
Why length matters for predictions
Calculators estimate ovulation by counting back from your next period. Most assume a 14-day luteal phase. If yours is 11 or 16 days, the estimated ovulation date can be off by two or three days. Knowing your own luteal length makes ovulation estimates more accurate.
Short luteal phase
A luteal phase of 10 days or fewer is often called a short luteal phase. Occasional short phases are common, especially after stopping hormonal contraception, during perimenopause, with intense exercise, low energy intake or stress. Whether a short luteal phase on its own affects fertility is still debated among specialists. Talk to a healthcare professional if:
- Your luteal phase is short in several cycles in a row.
- You have spotting for several days before most periods.
- You have been trying to conceive for a year, or six months if you are over 35.
Luteal phase in Bloom Private
Bloom Private starts with a standard estimate and personalizes your luteal phase after two cycles with detected ovulation, using the temperature, LH tests and cervical mucus you log. From then on, your period and fertile window estimates use your own luteal length instead of a fixed 14 days. The app is not a medical device and does not diagnose luteal phase problems.
Frequently Asked Questions
Usually 11 to 17 days, most often around 14. It tends to stay fairly stable for the same person.
A luteal phase of 10 days or fewer. Talk to a healthcare professional if it happens in several cycles in a row.
Find your ovulation day with basal body temperature or LH tests, then count the days until the day before your next period, over two or three cycles.