CAUSES OF INFERTILITY
Here are several potential causes of infertility in the female and in the male. Given the high incidence of male infertility, a complete evaluation of the male should always be performed. This is true even if a fertility problem has already been identified in the female. Very often there is a combination of female and male infertility factors.
The processes listed below must occur in order for a pregnancy to result.
The male must produce healthy sperm that can reach and fertilize an egg.
Tubal disease- the tubes must be open and free of obstructions that can be caused by endometriosis, scarring, infection, and other conditions. The eggs travel through the tubes from the ovaries to the uterus.
Cervical disease- the cervical mucus must support and nourish the sperm and it must be free of antisperm antibodies.
Ovulatory disease- healthy follicles must be recruited and mature eggs must be ovulated. These processes are controlled by hormonal interactions between the hypothalamus gland and the pituitary gland. FSH stimulates follicular development and a surge of luteinizing hormone (LH) stimulates ovulation.
Endometriosis- endometriosis can attach to, and penetrate, the reproductive organs including the tubes. It can cause blockage and other damage to these organs.
Uterine factor infertility- the uterus must be free of large obstructions such as polyps and fibroids.
The endometrium must thicken and develop to accept a developing embryo. Sometimes the endometrium does not develop appropriately and this is known as a “luteal phase” defect. The fertilized egg (embryo) must travel to, and implant in, the endometrium.
Female age / ovarian factor and infertility – as women age, their eggs loose the capacity to fertilize and develop.
The egg and sperm must combine to form a healthy embryo with a normal number of chromosomes.
The female must be healthy and capable of carrying a baby to term.
Abnormal processes, or diseases, affecting any one, or a combination, of these steps can lead to infertility. Typically, common causes include:
1) irregular or failed ovulation
2) significant endometriosis which can negatively effect many processes
3) damaged or blocked fallopian tubes
4) poor cervical mucus
5) a deformed uterus or the presence of large polyps and/or fibroids.
6) genetic disease
8) hormonal imbalances
9) inadequate sperm (poor quantity or quality)
Also, once the fetus begins development, the mother must be able to carry the baby to term. Spontaneous abortion is a major cause of infertility, which can have many causes but most often results from embryonic genetic abnormalities (i.e. wrong number of chromosomes).
One of the most frustrating diagnoses a couple can receive is unexplained infertility. It is our “nature” to seek the cause(s) of any medical condition negatively affecting our body.
“Unexplained” does not mean there is no cause of a couple’s infertility. Essentially, science and reproductive medicine have not advanced to the point where the cause can be identified. As more research is done, the numerous “undiscovered” causes of infertility will be delineated. An example is the advances made in male infertility. Many couples who had “mild male factor infertility” would probably have been diagnosed as “unexplained” several years ago. We have gotten much better in identifying the many aspects of sperm “quality”.
Most experts believe that a large segment of “unexplained infertility” is due to genetic disease in either the sperm or egg. Their may be problems with fertilization and embryonic development that have not been characterized by scientists.
LUTEAL PHASE DEFECT
The lining of the uterus must thicken and become much more vascular to provide the needed nutrients. Endometrial cells are “fast growing” and develop rapidly under the influence of estrogen and progesterone. Endometrial cells ability to rapidly grow and divide is the cause of endometriosis wherein the cells attach to, and sometimes penetrate, organs and other structures.
Too little progesterone can lead to a “luteal phase defect” wherein the endometrium does not develop properly. This defect is usually corrected by the administration of progesterone during the ovulatory cycle.
UTERIN FACTOR INFERTILITY
The uterus must be normally formed and free of large obstructions, such as endometriosis, fibroids and polyps for a successful pregnancy outcome. Some women are born with an abnormally shaped uterus such as the bicornuate uterus, which is the most common malformation. A woman may also have a septate uterus that is abnormally divided by a “wall”.
Surgery to correct these defects is effective in many women.
When the uterus is severely malformed it cannot accommodate a growing fetus. In these cases, a surrogate may be the only option for having a genetically related child. There are two types of surrogacy: 1) gestational where the surrogate carries the couple’s embryo created from an IVF cycle and 2) traditional where the surrogate uses her own eggs, fertilized by the father, usually in an IUI cycle.
A uterine fibroid (known as a leiomyoma) is a benign (non cancerous) growth composed of smooth muscle and connective tissue. Fibroids rarely become cancerous (less than 0.1%). The are found in over 50% of women between the ages of 30 and 50 although they may cause symptoms in only about 25%
Women with fibroids typically have a number of symptoms including:
The most common symptoms include heavy bleeding during menstruation. Large fibroids can also cause pressure and pain in the abdomen or lower back that some say feels like menstrual cramps.
Unusually large fibroids may press against the bladder and urinary tract and cause frequent urination or the urge to urinate, particularly during the night when a women is lying down.
As the fibroids grow larger, some women feel them as hard lumps in the lower abdomen.
Abnormal pain during intercourse (called dyspareunia)
Fibroid pressure against the rectum can cause constipation. Fibroids can degenerate during pregnancy causing pain and may cause premature labor.
Fibroids can decrease fertility by interfering with several reproductive processes:
*Alter the endometrial contour (uterine lining) and interfere with embryo implantation
*Enlarge the uterine cavity, or alter its contractility, interfering with sperm transport
*Persistent blood clots and may interfere with embryo implantation
*Fibroids can obstruct the openings to the fallopian tubes
*Increased risk of miscarriage
*Increased risk of premature labor
UTERINE FIBROIDS ETIOLOGY (CAUSES)
Proteins called growth factors may be responsible for some of the abnormalities leading to muscle over growth and fibroids. Scientists have identified chromosomes carrying a total of genes that may have an effect on fibroid growth. Some experts report that uterine fibroids are inherited from paternal genes (the father’s side).
The diagnosis and location of fibroids can sometimes be detected by a pelvic exam but a more precise diagnosis is established using ultrasound, the hysterosalpingogram, and/or the sonohysterogram. A hysterosalpingogram can detect fibroids that are in the uterine cavity. A sonohysterogram is performed by injecting saline into the uterine cavity and performing ultrasound examinations. The fluid creates a “contrast” making the fibroids easier to identify.
Surgery may not be necessary if the fibroids are very small or are located outside the uterine cavity. Large fibroids can usually be removed laparoscopically or sometimes using the hysteroscope.
A myomectomy is a surgical procedure where individual large fibroids are removed through an abdominal incision. Dependent on their location and numbers many fibroids can usually be removed laparoscopically (laparoscopic myomectomy), which dramatically reduces recovery time and pain. With laparoscopic myomectomy there is little on no hospital stay and one can resume normal activities in as little as three days.
Fibroids which are located inside the uterine cavity, can by removed through the cervix and vagina using the hysteroscope (hysteroscopic myomectomy). This is an outpatient procedure and requires no hospital stay.
Fibroids can sometimes be temporarily treated with Lupron, which is a GnRH agonist medication. Lupron has the following actions:
*Decreasing bleeding which is often encountered during the myomectomy
*Decreasing the size of the uterus for easier manipulation
*Creating a menopause like state that often shrinks the fibroids by 50%. The effect is temporary and the fibroids will re grow once medication has been discontinued.
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