Female Infertility Factors
40% of infertility cases are due to problems with the female reproductive system. There are a variety of factors that influence female infertility.
Age and Infertility
One of the most important factors influencing female infertility is age. A woman is born with about 400,000 eggs in each ovary. Over time, the number of eggs decreases, until about age 50. Around this age eggs stop dividing, menstruation stops and menopause begins.
Many women believe that their fertility doesn't begin to decline until they reach their late 30's or 40's. In actuality, a woman's fertility begins to decline by age 27, with a marked decline after age 35. This is because both the number and the quality of eggs produced by the ovaries declines over time. This decline also raises the risks of chromosomal abnormalities if a child is conceived. For this reason, it is important for women to start infertility treatment as early as possible, to ensure a higher probability of success and decrease the probability of chromosomal abnormalities. In women over the age of 44, it may not be possible to achieve a normal pregnancy without the use of donor eggs.
The ovaries are an important part of the female reproductive system. Each month, one of the two ovaries produces an egg, which develops in a fluid-filled sac called the follicle. When the egg is ready, it is released from the ovary and moves through the fallopian tubes to await fertilization. The ovaries also produce the hormones estrogen and progesterone, which along with hormones secreted from the pituitary gland and the hypothalamus regulate ovulation and the menstrual cycle.
About 25% of female infertility cases are caused by irregular or abnormal ovulation. Any disruption in the ovulation process makes it harder for the sperm to fertilize the egg. Ovarian problems can be hormonal or result from disease, such as Polycystic Ovarian Syndrome.
When a female has irregular menstrual cycles some hormonal evaluations are warranted. These hormonal evaluations include testing of the hormones of menopause (FSH and estradiol), testing for prolactin (a hormone that is usually produced during breastfeeding), testing for thyroid hormone (TSH), and testosterone. After determining which hormones are abnormal, we can determine the causes of anovulation, and based on that an appropriate treatment can be recommended.
Multiple treatments may be used for treatment of anovulation, including ovulation induction, either with Clomid or other oral agents, injectible medications such as Human Menopausal Gonadotropins (HMG), or correction of thyroid disease or high prolactin levels with thyroid hormone or prolactin lowering agents such as Parlodel or Dostinex.
One of the most common causes of female infertility is damage to the fallopian tubes. For successful fertilization to occur, the fallopian tubes must be free and open so that the sperm and the egg can meet. If this pathway is blocked or damaged, infertility can occur.
Pelvic adhesions, or scar tissue, are the most frequent cause of blocked fallopian tubes. Adhesions can be caused by infections such as pelvic inflammatory disease, endometriosis, past births, or previous surgical procedures. Pelvic adhesions can also form in the uterus, making it more difficult for the embryo to implant after fertilization.
To evaluate whether a patient has pelvic adhesions, the physician will first interview the patient and go over the details of their history to determine the reason that they may be having pelvic adhesions, which may include prior infection with chlamydia, prior pelvic surgery, or a history of painful menses, which may be an indication of endometriosis. If any of these are known to be true, or if there is any other factor that may point us toward tubal or uterine adhesions, an x-ray called a hysterosalpingogram will be ordered. A hysterosalpingogram is an x-ray in which the uterus and tubes are evaluated by pushing a radio opaque dye through the uterus and following the dye to see if it can pass through the tubes and also the uterus without getting caught in any adhesions. A hysterosalpingogram can also determine other causes of uterine and pelvic factor, including the presence of fibroids, presence of abnormally shaped uterus, and presence of polyps inside the uterus. Uterine factors may be an important cause of infertility as well as recurrent miscarriages.
The evaluation of the uterus for pelvic adhesions, fibroid uterus and polyps is an important part of the fertility evaluation, to both determine lack of implantation as well as causes of recurrent miscarriages.
After the hysterosalpingogram is performed, further testing may be required to evaluate the uterus and the tubes, including a laparoscopy and/or a hysteroscopy.
A laparoscopy is a procedure by which a camera is placed through the belly button to evaluate the pelvic cavity, including the uterus, ovaries and the tubes. Laparoscopy can be both a diagnostic as well as therapeutic procedure. A laparoscope may be used to evaluate the tubes, and then if there are adhesions or scar tissue next to the tubes, this procedure may be used to remove the adhesions, thereby increasing the chances of pregnancy.
A hysteroscopy is a procedure in which a small camera is used to evaluate the uterine cavity. Hysteroscopy can also be therapeutic and/or diagnostic. A hysteroscope may be used to remove scar tissue in the uterus as well as polyps and fibroids. This may be required prior to treatment of infertility to optimize implantation.
The cervix is the opening from the vagina into the uterus, which the sperm must pass through to reach the egg. Mucus in the cervix helps transport the sperm into the uterus. Injury or scarring due to surgery or infection can make the cervical opening smaller or reduce the amount of cervical mucus, making it harder for the sperm to reach the uterus.
In some cases, the consistency of the cervical mucus is too thick, preventing or inhibits the sperm from passing through. Some women also produce antibodies that identify sperm as foreign entities and kill them during the passage of sperm through the cervix.
At times, because cervical mucus may be hostile to the sperm, a test called “post-coital test” may be performed to evaluate the hostility of cervical mucus.
Post-coital testing is done as follows. The couple will have sexual intercourse at the time of the female ovulation. They will then come to the clinic and a portion of the cervical mucus will be removed and evaluated under the microscope. If, under the microscope, the cervical mucus shows that most of the sperm are non-motile and dead, this indicates that the cervical mucus may have hostility towards the sperm. On the other hand, if the sperm are moving within the cervical mucus, that is a sign that the cervical mucus may not be the cause of infertility and is not hostile to the sperm.
If cervical mucus is suspected to be the cause of infertility, then the most appropriate treatment is intrauterine insemination (IUI). Intrauterine insemination is a process by which, at the time of ovulation of the female partner the sperm of the male partner is obtained, washed with sperm wash media and placed through the cervix into the top of the uterus to bypass cervical mucus and increase the odds of pregnancy.
Back to Infertility