Structural Causes of Infertility
A common cause of female infertility is a blockage of the fallopian tubes. A blockage of one or both tubes can prevent sperm from meeting and fertilizing an egg.
Fallopian blockage may result from several possible causes:
- Hydrosalpinx, when a fallopian tube fills with fluid.
- Tubal scarring or adhesions from salpingitis, a previously undetected or untreated infection of the tubes, including infection from sexual transmissions.
- Endometriosis lesions within the uterine lining.
Pelvic inflammatory disease (PID) is a general term for infection and inflammation of the upper reproductive organs, including endometriosis, salpingitis, and oophoritis, an infection and inflammation of the ovaries.
In addition to preventing conception, blocked fallopian tubes can cause ectopic pregnancy, in which a fertilized egg is unable to move to the uterus for implantation and starts to grow within the tiny fallopian tube, ovary or abdominal cavity.
The most common causes of hydrosalpinx are undiagnosed or untreated sexually transmitted diseases chlamydia and gonorrhea. Other possible causes are use of IUDs, endometriosis, and abdominal surgery.
Whether from infection or trauma, injury to the end of the fallopian tube (the ampulla) and its delicate fingers (the fimbria) can cause the end of the fallopian tube to close. Glands within the tube produce a watery fluid that collects and produces a sausage shaped swelling. The fluid is toxic to early embryo development or may mechanically flush out the embryo from the uterus.
Hydrosalpinx can create or worsen infertility, either by preventing ovulated eggs from meeting with sperm or by affecting embryos in the uterus. If hydrosalpinx is undetected, use of fertility drugs can increase the fluid build-up.
Additionally, the common diagnostic procedure of hysterosalpingogram (HSG) – an X-ray of the inside of the uterus and fallopian tubes and surrounding area – can inadvertently introduce bacteria into the tubes, possibly resulting in serious infection, and may also decrease the odds of successful in vitro fertilization (IVF).
Women of any age can develop ovarian cysts, fluid-filled sacs on one or both ovaries. You can see these in an ultrasound image as bubble-like structures filled with fluid. A normal ovary can have small cysts remaining from ruptured egg follicles.
Most ovarian cysts are benign, or not cancerous and usually disappear on their own and produce no symptoms.
However, ovarian cysts are sometimes associated with abdominal or pelvic pain, spotting in between menstrual periods, and/or infertility. Various types of cysts include:
- Hemorrhagic cyst, when bleeding is also present
- Dermoid cyst — Comprised of the same tissue as skin, fat, bone, hair, or cartilage; may become inflamed or cause ovarian torsion (twisting)
- Endometrioid cyst – A cyst caused by endometriosis, a common cause of female infertility
- Polycystic ovary – These are usually twice the normal size with many small cysts on the outside of the ovary and are seen in women both with and without polycystic ovary syndrome (PCOS).
Benign (non-cancerous) tumors, called myomata uteri or fibroids, are common in the uterus. These often go undetected and cause no problems, although fibroids can be the source of excessive and frequent menstrual periods, pelvic pain, infertility, and recurrent pregnancy loss.
In a few women, these tumors can lead to severe anemia as a result of excessive uterine bleeding. Other symptoms might include pelvic pressure on the woman’s bladder or rectum, which may result in frequent urination or constipation. In addition, an enlarged uterus can cause some women to experience pain during sexual intercourse.
Other Uterine Abnormalities
Some women are misdiagnosed as infertile when in fact they were born with uterine abnormalities (congenital), including a double uterus (bicornuate), uterine septum, and a uterus in which only one side has formed (unicornuate).
For many women, an abnormally shaped or positioned uterus is not likely to prevent fertilization but can interfere with uterine implantation or the ability to carry a pregnancy to term. Some of these conditions can be corrected through surgery. In other cases, women suffering from such conditions cannot expect a normal pregnancy and must rely on a gestational carrier.