Corpus luteum cysts
If you know your ovulation day with certainty, and you have got neither your period nor a positive pregnancy test when your luteal phase should normally be over, you may have a corpus luteum cyst.
When you ovulate, a mature egg cell is released from the follicle (or follicular sac) and starts its journey though the fallopian tube towards the uterus. The ruptured follicle transforms into a secretory gland known as the the corpus luteum (“yellow body” in latin), hence the name luteal phase. The corpus luteum now begins to produce the hormone progesterone, which keeps the uterine lining intact and ready for a fertilized egg to implant. If conception doesn’t happen, the corpus luteum disintegrates, and progesterone levels drop until the uterine lining is no longer sustained. The lining is shed and you get your period.
Sometimes, however, the follicular sac reseals after having released the egg, and fluid accumulates inside it. This causes the corpus luteum to grow into a cyst, which keeps producing progesterone beyond the usual luteal phase length. This is called a corpus luteum cyst. These cysts are harmless and do usually not cause any other symptoms than the missed period, but if they grow big they may cause pelvic or abdominal pain. Corpus luteum cysts usually disappear by themselves after a few weeks
A corpus luteum cyst will not prevent conception, nor will it usually affect the pregnancy. If you aren’t pregnant, however, it can be frustrating to wait for a new cycle and another chance of conception. If you suspect that you may have a corpus luteum cyst, contact your physician or your gyneacologist. In most cases, ultrasound will confirm the diagnosis. You may be asked to come back in three months to check that the cyst has disappeared.