Structural Causes
Tubal Abnormalities
The fallopian tubes are two hollow “tubes” attached to the left and right side of the uterus. Each tube extends from the uterus to the ovary and their function is to catch the egg as it is released from the ovary. The ends of the fallopian tube are flared and have delicate fingerlike structures called fimbriae. When the ovary releases an egg or oocyte, the fimbriae pick up the egg and direct it into the tube. As the egg passes through the fallopian tube the egg receives nutrition and a perfect environment for fertilization. Egg and sperm usually meet in the distal portion of the tube, where fertilization occurs. It is vital that the fallopian tube is open and functioning properly to allow egg and sperm to meet and the fertilized egg to move to the uterus for implantation.
Tubes that have been damaged by previous infection or endometriosis can severely affect a couple’s chance for pregnancy. There are also congenital abnormalities of the fallopian tubes that can make egg pick up difficult.
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Causes of Infertility
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Tubal Blockage
Women who have had pelvic infections, surgery or endometriosis which involve inflammation can cause scarring around the uterus and fallopian tubes. Women who have had an ectopic pregnancy can also have tubal blockage. Blockage can be caused by various other conditions such as:
- Pelvic infections (such as pelvic inflammatory disease and sexually transmitted diseases)
- A ruptured appendix or surgery in the pelvis or lower abdomen
- A tubal or ectopic pregnancy in the fallopian tubes
- Malformation of the fallopian tubes
- Endometriosis
- Pelvic adhesions between normally unconnected structures in the uterus or pelvis
- Congenital abnormalities
Hydrosalpinx
A blocked fallopian tube that becomes filled with liquid is called a hydrosalpinx. These not only cause infertility, but can also reduce the effectiveness of other infertility treatments. The condition occurs when injury to the fallopian tube, usually from infection, causes the end of the tube to close. As a result, fluid collects in the tube and causes it to swell. This fluid would normally leak out the end of the tube but since the tube is blocked it actually leaks back into the uterus. This fluid has been shown to decrease the chances for conception by a significant amount. If an embryo is implanted in the uterus using IVF this tubal backflow into the uterus can decrease the chances for success by one third to one half unless treated ahead of time.
Symptoms of Tubal Blockage
The most common symptom of tubal blockage is infertility.
Diagnosis of Tubal Damage
Tubal factor infertility is a very common problem and because of this we routinely test to determine if the tubes are open and undamaged as a part of the normal fertility workup. At IVF Plano we routinely use one of two types of diagnostic tests to check for tubal patency a hysterosalpingogram (HSG) and a surgical procedure, diagnostic laparoscopy.
Read more about Hydrosalpinx
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Uterine Abnormalities
Uterine abnormalities such as fibroids, polyps, uterine septums, or other congenital abnormalities can lower a woman’s chances for conception or increase the chances for miscarriage. These abnormalities can make it difficult for an embryo to implant or be nurtured during pregnancy. Fortunately for patients with these uterine abnormalities, surgical correction can in most cases correct the fertility problem and allow normal conception and pregnancy.
Read more about The Evaluation of the Uterus
Uterine Septum
The uterus in a female fetus forms from two separate halves that begin in the upper abdomen and travel downward as the fetus matures. The left and right sections of the uterus migrate down in the abdominal cavity and fuse together to create a hollow organ. As they fuse together the tissue in the middle, once the outer walls, reabsorbs to create the central cavity where the baby will grow. In some women this re-absorption of the middle wall is incomplete resulting in a thick band of remaining tissue, a uterine septum, in the middle of the cavity. Uterine septums can be found in many different shapes and sizes. Some consist of a small tissue bands along the top of the uterus, while others deeply divide the uterus into two distinct segments.
Uterine septums are not normal uterine tissue and can lead to miscarriages by preventing normal implantation of a fertilized embryo. If the embryo implants on the septum the chance of a successful pregnancy is greatly decreased. The tissue of the septum has a very poor blood supply and therefore decreases the supply of nutrition to the implanting embryo resulting commonly in a loss of the pregnancy.
In most cases, unless the septum is so pronounced and extends into the vaginal canal most patients do not realize that that they have this condition and it is only discovered when the patient is examined for infertility, has repetitive miscarriages or is found during an annual PAP smear.
Treatments for Uterine Septum
In most cases a uterine septum can be corrected surgically by hysteroscopic resection. In the surgical repair of a uterine septum the additional tissue band is resected, or cut so that the entire top of the uterus enlarges, creating a more normal area for implantation to occur. Once this procedure has been performed, the uterus is much more capable of carrying a pregnancy to term.
Note: Uterine abnormalities other that septums are not usually repaired as the opportunity to increase the chance for pregnancy does not improve greatly with surgery.
Intrauterine Scarring and Asherman’s Syndrome
Intrauterine scarring is scar tissue that forms within the uterus and is most commonly the result of an injury to the uterine cavity by a severe intrauterine infection, an extensive D&C procedure, or other intrauterine surgeries. As a part of the normal healing process after an injury, the walls of the uterus may stick together to form adhesions. These intrauterine adhesions can be limited to a few distinct bands of scar tissue or they can affect the entire uterine cavity. This can sometimes cause the endometrial lining to be too thin for an embryo to attach. In severe cases the scarring and adhesions can be so extensive that there is a complete cessation of menstrual flow. Severe cases of intrauterine scarring are called Asherman’s syndrome.
Treatment for Intrauterine Scarring
Treatments for intrauterine scarring usually involve the repair and/or removal of existing scar tissue by hysteroscopy. Patients are then given supplemental estrogen to rebuild the endometrial lining of the uterus.
Read more about Intrauterine Adhesions
Uterine Polyps
A polyp is an overgrowth of tissue in the lining or endometrium of the uterus. Even though this tissue is considered to be “normal” in origin, physicians consider the best treatment to be surgical removal of the polyp. Most polyps that are very small and do not represent a problem with fertility. However, large polyps - or multiple polyps - can interfere with fertility, increase the chance for miscarriage and cause heavy, irregular, or bleeding between menstrual cycles.
Treatments for Uterine Polyps
Uterine polyps are easily removed (called polypectomy) during a routine hysteroscopy.
Uterine Fibroids
Uterine fibroids are noncancerous growths that can occur in and on the uterus. Also called fibromyomas, leiomyomas or myomas, uterine fibroids are not usually associated with an increased risk of uterine cancer but can affect a women’s chance for conception. It is thought that fibroids can affect conception by decreasing the supply of blood flow to the endometrium preventing the attachment of an embryo. They may also obstruct the fallopian tube openings into the uterus and certain types of fibroids may increase the risk of miscarriage or pregnancy complications.
No one knows what causes uterine fibroids, but their growth seems to depend on estrogen and progesterone levels. Fibroids tend to shrink or disappear after menopause when estrogen levels fall. Fibroids also appear to have some family history or genetic connection. Women whose mothers and sisters have uterine fibroids are more likely to have them as well. African-American women tend to get uterine fibroids two to three times as often as other women and also tend to have more symptoms.
Fibroids come in all sizes and shapes. They can vary in size from a few millimeters to the size of a basketball.
Types of Fibroids:
- Intramural fibroids are in the muscular wall of the uterus.
- Submucosal fibroids grow just under the inside surface of the uterus, and may protrude into the uterine cavity where the baby is supposed to be.
- Subserosal fibroids grow on the outside wall of the uterus.
- Pedunculated fibroids usually grow outside of the uterus, attached to the uterus by a base or stalk.
Symptoms of Uterine Fibroids
Most often, uterine fibroids cause no symptoms at all and most women don’t realize they have them. When women do experience symptoms from uterine fibroids, they can include:
- Prolonged menstrual periods (7 days or longer) with heavy bleeding
- Bloating, fullness or pain in the belly or pelvis
- Constipation
- Pain during intercourse or bowel movements
- Anemia
Diagnosis of Uterine Fibroids
There are different ways to determine if someone has fibroids. Large to moderate fibroids can be felt during a manual pelvic examination. Smaller fibroids require imaging tests to confirm their presence and their location in the uterus. Dr. Douglas uses an ultrasound probe, inserted into the vagina to look for fibroids. Ultrasound machines use high-frequency sound waves that reflect off the uterus and pelvic structures. Fibroids are displayed on a video screen and can be measured and evaluated for position within the uterus. Hysterosalpingograms and sonohysterograms can be used to see if the fibroids are inside the uterine cavity.
Treatment of Uterine Fibroids
Most fertility specialists consider the location and size to be the deciding factor whether or not to remove the fibroid. Dr. Douglas considers the physical characteristics of the fibroid, the size and the location in the uterus as well as patient specific conditions before deciding the best course of action for the treatment of fibroids.
Read more about Abnormal Uterine Bleeding
Hostile Cervical Mucus
Another cause of female infertility is hostile cervical mucus. Cervical mucus that is too thick can prevent sperm from passing through the cervix and into the uterine cavity. Hostile cervical mucus can occur due to the presence of antisperm antibodies, infection, low hormone levels, damage to the cervix from previous surgeries, or abnormal sperm. Dr. Douglas can perform post-coital testing to determine whether hostile cervical mucus plays a role in a couple's infertility problem.
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