Corpus luteum: definition and meaning
The corpus luteum is a temporary gland that forms in the ovary from the follicle that released an egg at ovulation. Its name is Latin for "yellow body". It makes progesterone and some estrogen to prepare the uterine lining for pregnancy. If no pregnancy happens, it breaks down after about 10 to 14 days, hormones fall and your period starts.
How it works in your cycle
- At ovulation, the mature follicle releases its egg.
- The empty follicle reorganizes into the corpus luteum.
- It pumps out progesterone, which thickens and steadies the endometrium and raises basal body temperature.
- No pregnancy: it shrinks into scar tissue (corpus albicans), progesterone drops, and your period begins.
- Pregnancy: hCG from the embryo keeps it going until the placenta takes over at around 10 to 12 weeks.
Why it matters
The corpus luteum is the engine of your luteal phase. Its steady life span is why the luteal phase is fairly constant, usually 11 to 17 days, while the follicular phase varies more. A short-lived corpus luteum is one idea behind luteal phase defect.
It also matters for mood. The rise and later fall of its progesterone, and of progesterone's brain-active byproduct allopregnanolone, is linked to the premenstrual mood shifts many people feel. In PMDD the brain seems extra sensitive to these normal changes.
Corpus luteum cysts
Sometimes the corpus luteum fills with fluid and forms a cyst. These are common and usually harmless, often disappearing within a few cycles. See ovarian cyst.
Get urgent care for sudden, severe one-sided pelvic pain, especially with fever, vomiting or fainting, which can mean a ruptured or twisted cyst, or an ectopic pregnancy.
Frequently asked questions
How long does the corpus luteum last?
About 10 to 14 days if you're not pregnant. In pregnancy it keeps working for roughly the first 10 to 12 weeks.
Can you feel the corpus luteum?
Usually not. A corpus luteum cyst can sometimes cause a dull ache on one side.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Progesterone: definition and meaningProgesterone is the hormone made after ovulation that prepares the uterus for pregnancy. Its role in the luteal phase, PMS, mood, sleep and temperature.
Luteal phase: definition and meaningThe luteal phase is the part of your cycle from ovulation to your next period, usually 12 to 14 days. Hormones, mood, PMS and why it matters.
Ovulation: definition and meaningOvulation is when an ovary releases an egg, usually 12 to 14 days before your next period. Signs, timing, the fertile window, and how it affects mood.Luteal phase: why feelings get louderWhat the luteal phase is, how long it lasts, why progesterone rises and falls, and the common symptoms: PMS, cravings, low energy and mood changes.
What is a luteal phase defect?A luteal phase defect means the time after ovulation is too short or makes too little progesterone. What it means, the debate, and when to ask a doctor.