Possible Causes of Unexplained Infertility
There are a number of things that may underlie your unexplained infertility. Through patience and careful testing it may be possible to attribute your infertility to one of this underlying factors. Fertility treatment can then proceed based on the diagnosis.
Abnormal Fallopian Tubes
Sometimes, unexplained infertility is actually caused by tiny abnormalities in your fallopian tubes. Your fallopian tubes contain structures that help to sweep your eggs inside. The fimbria are finger-like projections located at the ends of each fallopian tube. They grab onto your ovaries, helping to coax your egg inside. Your fallopian tubes also contain cilia, tiny hairs that help to direct your egg down into your uterus. Sometimes, there are problems with the fimbria or cilia, which can prevent your eggs from being fertilized.
Though your ovaries house thousands of eggs, not all of these eggs are suitable for fertilization and division. Eggs need to be of the proper shape and size and must contain the right chromosomes to be successfully fertilized and implanted. If your egg quality is compromised in any way, you may have problems getting pregnant.
Luteinized Unruptured Follicle (LUF) Syndrome
During ovulation, it is possible for your eggs to become trapped in the sac that protects them. While maturing, your eggs are kept inside of a tiny membrane, called a follicle. When stimulated by certain hormones, this follicle bursts to release an egg. The egg then moves into the fallopian tube and the leftover membrane becomes the corpus luteum. Sometimes though, a follicle can become a corpus luteum before rupturing, trapping your egg inside. As a result, ovulation never occurs.
Abnormal Luteal Phase
After your egg has been released from your ovary, a phase, called the luteal phase, begins. During this phase, the corpus luteum begins to produce progesterone. This hormone stimulates your uterus to prepare the endometrial lining for implantation. Sometimes though, there are problems with the levels of progesterone. These levels may rise too quickly or too slowly, or progesterone may not be produced for a long enough period. As a result, the endometrium doesn't become properly prepared for implantation.
Your immune system is designed to protect you from invading cells and organisms. It is responsible for killing off disease and infection. Sometimes though, the immune system can become confused, and begin to kill your body's natural cells. Many women have immune systems that attack their own eggs. Your partner's immune system may even be attacking sperm cells, causing them to stick together, become immobilized, or even die.