Causes of Female Infertility
These are the possible causes of Female Infertility:
- Hormone Imbalance
- Physical Abnormalities
- Uterine Factors
When there is an inability for a woman to ovulate or release an egg then this cause female infertility. Hormonal problems can be root of female infertility. A woman may be producing too little of one hormone or too much of another hormone. The good news is that it’s not difficult to detect hormonal imbalances, and fertility treatments can be administered relatively simply. Such is the case with the conditions listed here.
Hormonal imbalances can sometimes be traced back to the primary glands (hypothalamus, thyroid and pituitary) that produce reproductive hormones. The hypothalamus, pituitary and ovaries send signals back and forth during the reproductive process that cause changes in hormone production.
Hypothalamus: This gland can be affected by stress, birth control pills, disease and some medications.
Thyroid: An underactive thyroid gland causes hypothyroidism and can be characterized by excessive levels of the hormone prolactin, which interferes with ovulation.
Pituitary: Microscopic tumors (prolactinomas) on the pituitary gland can secrete the hormone prolactin, which interferes with ovulation.
One of the leading causes of female infertility is ovulation. It occurs in about 25% of cases. Some women ovulate irregularly or do not ovulate at all (this is called anovulation). When women have problems with ovulation it’s usually because they have hormonal imbalances such as too much prolactin (a milk-producing hormone that suppresses ovulation) or too many androgens.
Androgens, or male sex hormones, the most important of which is testosterone, promote the development of male sex characteristics. Both males and females have the same starting products of androgens. Androgen levels rise continuously between the ages of seven and thirteen in puberty, prompting the appearance of axillary and pubic hair. They are also responsible for sex drive, and may be converted to estrogen after menopause when ovarian estrogens are no longer produced. An imbalance can cause the shift for women to have too many androgens or men to have too little.
Polycystic Ovarian Syndrome (PCOS)
Polycystic Ovarian Syndrome (PCOS) is a condition in which hormone imbalances interfere with ovulation. The adrenal glands and ovaries produce excessive amounts of male hormone, which leads to an abnormally high production of luteinizing hormone (LH) and an abnormally low production of follicle-stimulating hormone (FSH). As a result, the ovary fills with cysts of immature follicles that are unable to generate eggs.
Women with PCOS may experience:
- Irregular periods
- Enlarged ovaries
- Excessive facial and body hair
- Oily skin
Why do women with Polycystic Ovarian Syndrome (PCOS) have trouble with their menstrual cycle?
The ovaries are two small organs, one on each side of a woman’s uterus. A woman’s ovaries have follicles, which are tiny sacs filled with liquid that hold the eggs. These sacs are also called cysts. Each month about 20 eggs start to mature, but usually only one becomes dominant. As the one egg grows, the follicle accumulates fluid in it. When that egg matures, the follicle breaks open to release the egg so it can travel through the fallopian tube for fertilization. When the single egg leaves the follicle then ovulation takes place.
In women who have PCOS, the ovary doesn’t make all of the hormones it needs for any of the eggs to fully mature. They may start to grow and accumulate fluid but the eggs don’t grow large enough. Instead, some may remain as cysts. Consequently, no egg matures or is released, ovulation does not occur and the hormone progesterone is not made. Without progesterone, a woman’s menstrual cycle is irregular or absent. Also, the cysts produce male hormones, which continue to prevent ovulation.
When a woman who is under 40 years of age and her ovaries are not producing sufficient hormones to sustain ovulation and menstruation then she is deemed to be prematurely menopausal. Premature menopause, also known as Premature Ovarian Failure (POF), occurs in 1% to 4% of women and it occurs when a woman has prematurely depleted her supply of eggs.
Abnormal Cervical Mucous
For successful impregnation to occur normal cervical secretions are a vital component. Many women notice a change in the consistency of their cervical mucous throughout the menstrual cycle. Around the time of ovulation cervical mucous is thin and watery to make it easy for sperm to enter the uterus.
Abnormal cervical mucous is a rare condition that involves at least one of the following:
- Cervical mucous is too thick for sperm to swim through even during ovulation.
- Cervical glands do not produce enough mucous.
- Surgery or infection can damage the glands that produce cervical secretions in certain cases. This can cause mucous abnormalities.
Endometriosis is a benign disease defined by the presence of ectopic (outside the uterus) endometrial tissue and stroma that can be associated with pelvic pain and female infertility. It displays a broad spectrum of clinical manifestations, is prone to progression and recurrence, and often presents difficult clinical management problems for women and their clinicians. Endometriosis is a major cause of female infertility and a woman might not even know it because it may be present with no symptoms. Some studies indicate that endometriosis decreases pregnancy rates even though there may be little visible organ damage.
Endometriosis lesions can be found anywhere in the pelvic cavity, namely on the ovaries, the fallopian tubes, and on the pelvic sidewall. Other common sites include the uterosacral ligaments, the cul-de-sac, the Pouch of Douglas, and in the rectal-vaginal septum. It can also be found in caesarian-section scars, laparoscopy or laparotomy scars, and on the bladder, bowel, intestines, colon, appendix, and rectum. In rare cases, endometriosis has been found inside the vagina, inside the bladder, on the skin, in the lung, spine, and brain.
Endometriosis can also cause scar tissue and adhesions to develop that can distort a woman’s internal anatomy. In advanced stages, internal organs may fuse together, causing a condition known as a “frozen pelvis.”
The female infertility associated with endometriosis has been attributed to three primary mechanisms: distorted adnexal anatomy that inhibits or prevents ovum capture after ovulation, interference with oocyte development or early embryogenesis, and reduced endometrial receptivity.
Symptoms of Endometriosis
Pelvic pain is the most common symptom of endometriosis. The pain often correlates to the menstrual cycle, but a woman with endometriosis may also experience pain that doesn’t correlate to her cycle. The pain of endometriosis is so severe and debilitating for many women that it impacts their lives drastically. Other symptoms could be diarrhoea or constipation, or abdominal bloating (in connection with menstruation), heavy or irregular bleeding, or fatigue. Female infertility is another common known symptom of endometriosis. An estimated 30-40% of women with endometriosis are subfertile.
The pain of endometriosis can be felt:
- before, during or after menstruation
- during ovulation
- in the bowel during menstruation
- when passing urine
- during or after sexual intercourse
- in the lower back region
The fallopian tubes are the channels between the uterus and the ovaries. Sometimes both tubes are blocked, one is blocked or there is scarring or other damage to the tube. It may become blocked due to infections, endometriosis, scar tissue, adhesions, and damaged tube ends (fimbria). Blocked tubes make pregnancy next to impossible even if you ovulate regularly. The egg cannot get to the uterus and sperm can’t get to the egg.
The main treatment is usually IVF. However, if the blockage is found to be limited to a small area it might be possible to clear it by laparoscopy or open tubal surgery to remove the blocked portion. Infections such as chlamydia tend to damage the whole length of the tube so surgery is a less likely option. A laparoscopy is usually carried out to determine which treatment is the most appropriate for you.
Uterine factors should always be considered although abnormalities of the uterus are a relatively uncommon cause of female infertility. The anatomic uterine abnormalities that may adversely affect fertility include congenital malformations, leiomyomas (fibroids), intrauterine adhesions (scarring), and endometrial polyps. These same abnormalities can also adversely affect pregnancy outcome such as recurrent pregnancy loss.
- Congenital Uterine Malformations
- Uterine Leiomyomas (fibroids)
- Intra-uterine adhesions (Ashermans Syndrome)
- Endometrial polyps
Congenital Uterine Malformations
While pregnancy loss and obstetric complications have been associated with developmental uterine, the ability to conceive is generally not affected.
If this is discovered during the evaluation such irregularities cannot be regarded as the likely cause or as a contributing cause of female infertility. It can only be seen as another obstacle that must be considered when choosing from the range of fertility treatment options. Treatments that are associated with substantial risk for multi-fetal gestations (superovulation with IUI, IVF) present even greater risks to women with uterine malformations.
These are the different types of problems of the uterus:
A bicornuate uterus
- (a womb with two ‘horns’) is the most common. Instead of the womb being pear-shaped, it is shaped like a heart with a deep indentation at the top. The baby has less space to grow than in a normally shaped womb.
A unicornuate uterus
- (a womb with one ‘horn’) happens when the tissue that forms the womb does not develop properly. This is a very rare condition. A unicornuate uterus is just half the size of a normal womb and the woman has only one fallopian tube. However, she usually has two ovaries. Women with a unicornuate uterus may have difficulties conceiving because they have only one fallopian tube. However, pregnancy in women with this condition is far from unknown.
A uterus didelphys
- a double uterus is when the uterus has two inner cavities. Each cavity may lead to its own cervix and vagina, so the woman has two cervixes and two vaginas. This is very rare.
A septate uterus
- is where the inside of the uterus is divided by a wall (septum). The septum may extend only part way into the uterus or it may reach as far as the cervix. Among all congenital uterine abnormalities, the septate uterus is both the most common and the one most highly associated with reproductive failure and obstetrical complications. This includes first and second trimester miscarriage, preterm delivery, fetal malpresentation, intrauterine growth retardation, and female infertility. Normally, the uterus leans forwards over the top of the bladder. Doctors call this position “anteverted” and “anteflexed”. Some women have a tilted uterus (which may also be described as “backward”, “retroflexed”, “retroverted” or “tipped”). The uterus leans away from the bladder rather than over it. A tilted uterus does not make a woman less fertile.
Uterine abnormalities do not prevent a woman from getting pregnant, but they may make it more difficult for her to carry a baby for the full nine months of pregnancy.
Uterine Leiomyomas (Fibroids)
Evidence indicates that pregnancy and implantation rates are significantly lower in women with submucous myomas but not in those with subserosal or intramural myomas that do not encroach on or clearly distort the endometrial cavity, at least when they are relatively modest in size (less than 5 – 7 cm).
Judgments concerning the indications for surgical intervention in infertile women with myomas are similar with that in women with congenital uterine malformations. Like septate uteri, submucous myomas are associated with a decreased probability for successful pregnancy. The management of uterine myomas in infertile women must be highly individualized.
The relative risks, benefits, and consequences of different surgical treatments must be taken into consideration. In addition, so should age, ovarian reserve, reproductive history, duration of infertility, other female infertility factors and the treatment required. Plus the size, number, and location of myomas should be considered.
Intrauterine Adhesions (Asherman’s Syndrome)
Asherman’s Syndrome is an acquired uterine disease. It is characterized by the formation of adhesions (scar tissue) in the uterus. In many cases the front and back walls of the uterus stick to one another. In other cases, adhesions only occur in a small portion of the uterus. The extent of the adhesions defines whether the case is mild, moderate or severe.
Most patients with Asherman’s have scanty or absent periods (amenorrhea) while others have normal periods. Some patients have no periods but feel pain each month that their period would normally arrive. This pain may indicate that menstruation is occurring but the blood cannot exit the uterus because the cervix is blocked by adhesions. Other symptoms include recurrent pregnancy loss and placenta accreta.
Most commonly, intrauterine adhesions occur after a dilatation and curettage (D&C) that was performed because of a miscarriage or because of retained placenta with or without hemorrhage after a delivery. Adhesions sometimes also occur in other situations, such as after an elective abortion, ceasarean section, uterine surgery (for example, after surgery to remove fibroids), or as a result of pelvic tuberculosis. The more D&Cs done after a delivery (especially in the second to fourth week after delivery), the higher is the likeliness of developing adhesions
Chronic inflammatory or infectious insults, notably genital tuberculosis, can also result in intrauterine adhesions. Hysteroscopy is the method of choice for treatment of intrauterine adhesions. It is safer and more effective than blind curettage.
Polyps in infertile women occur in approximately 3% – 5% of cases. It is higher in women with other symptoms (such as abnormal bleeding) and may also be higher in those with endometriosis. Polyps can be identified by HSG or transvaginal ultrasound.