Before we talk about female infertility, we have to learn how natural fertilization works. The female reproductive system is very complex. All the eggs that a woman has throughout her life were already there when she was born. One egg is released every month during the menstrual cycle. The egg goes from the ovaries, through the Fallopian tube and to the uterus. A pregnancy starts when a sperm fertilizes an egg in the uterus. However, if a woman does not become pregnant during this time, she will start to menstruate and can try again the next month.

Hormones produced in the hypothalamus, pituitary gland, and ovaries regulate the stages of the menstrual cycle. The hypothalamus secretes a hormone called gonadotropin-releasing hormone or GnRH for short. This hormone directly stimulates the pituitary gland to secrete the LH and FSH hormones. These hormones then enter the bloodstream and affect the ovaries. To fully understand female infertility we will analyze the dysfunctions of different parts of the reproductive system separately.

The ovaries

The ovaries are responsible for carrying the eggs throughout your life. The hypothalamus and the pituitary gland make them produce estrogen, progesterone and, testosterone. The ovaries use these hormones to control the menstrual cycle and pregnancy. Now we will address the disorders that occur in the ovaries.

Ovulation disorders

Having an ovulation disorder means that you ovulate infrequently or not at all. The sperm will not be able to fertilize the egg if there is no egg to fertilize in the first place! Natural ovulation occurs monthly during the menstrual cycle. During ovulation, the egg leaves the ovaries and enters the Fallopian tube. Normally, women who experience breast and lower abdomen pain and bleeding every month have a normal ovulation cycle. The following are a few causes of ovulation disorders.

• Polycystic ovary syndrome (PCOS)

This is when a hormone imbalance causes irregular ovulation. Obesity, insulin resistance, appearance of hair on the face and body, and acne are some symptoms of this syndrome. It is the most common cause of female infertility.

• Pituitary gland and hypothalamus disorders

A sharp increase or decrease in weight, strenuous exercise, and stress can cause imbalances in the hormones released by the pituitary gland and hypothalamus. Consequently, these imbalances may cause irregularity in ovulation and the menstrual cycle.

• Premature ovarian failure (POF)

This refers to the malfunction of the ovaries in women under the age of 40. The ovaries stop producing eggs, estrogen levels fall, and the menstrual cycle stops. This disorder could occur due to autoimmune or genetic diseases or after chemotherapy.

• Systemic diseases

Hypo and hyperthyroidism, chronic liver and kidney diseases, and turner syndrome can also negatively affect ovulation.

• High blood prolactin levels

Prolactin is a hormone produced by the pituitary gland. Overproduction of this hormone causes a decrease in estrogen. These changes can cause infertility. Keep in mind that the pituitary gland isn’t always responsible for this overproduction and that certain drugs can have the same effect.

Old age

Age is an important factor when it comes to pregnancy. Your eggs are as old as you are. As a women ages, her eggs decrease in number and quality. Every woman has around 300,000 follicles (a follicle is a sac that contains immature eggs) at the age of puberty. One egg is released from its follicle every month during ovulation. Smoking, radiotherapy, chemotherapy, and autoimmune diseases can destroy these follicles.

Unnatural fallopian tubes/pelvic adhesions

Pelvic adhesions and diseases of the Fallopian tubes prevent the natural movement of eggs and sperm in the Fallopian tubes. The most important cause of Fallopian tube disorders is pelvic inflammatory disease (PID). PID is an infection of the uterus and Fallopian tubes caused by STDs such as chlamydia and gonorrhea. Severe endometriosis can also have a negative effect on the function of the Fallopian tubes. Adhesions caused by laparotomy, inflammatory bowel disease, and PID could lead to a blocking of the Fallopian tubes.

The uterus

Unnatural uterus structure and changes in the tissue of the endometrium (the endometrium is the inner lining of the uterus) could cause issues in the implantation of the fertilized egg in the endometrium. They can also cause a miscarriage.

Uterine fibroids

A uterine fibroid or a leiomyoma is a benign tumor made up of the soft muscles of the uterus. A particular type of this tumor called a submucosal leiomyoma can cause issues in the implantation process and lower the likelihood of a successful pregnancy. However, other cases do not cause these issues.

Unnatural uterus anatomy

Adhesions in the uterus caused by surgery, infection, endometrial polyps, and congenital disorders may also cause problems for the implantation process.

Weak luteal phase of the menstrual cycle

During the luteal phase of the menstrual cycle, after releasing the egg, the corpus luteum (a temporary structure in the ovaries) produces the progesterone hormone. Progesterone helps the embryo implant more easily in the endometrium. In the case that the corpus luteum cannot produce enough hormones, the embryo will not be able to implant in the uterus.

Endometriosis

This disease occurs when endometrial tissue grows somewhere outside the uterus. It reduces the chances of pregnancy in different ways. The removal of this tissue through surgery can leave scars in the uterus. These scars may cause anatomical disorders and pelvic adhesions.

Endometrioma is what we call endometriosis that occurs in or on an ovary. The removal of an endometrioma can also have a negative effect on the likelihood of getting pregnant.

Endometriosis causes the production of inflammatory factors that affect the natural processes of ovulation, implantation, and gestation.

Immune disorders that cause female infertility

Antiphospholipid syndrome

This syndrome is an autoimmune disease where the immune system may attack the embryo and cause a miscarriage.

Celiac disease

Women who suffer from untreated celiac disease have a higher chance of having a miscarriage. The rates of infertility are also higher among these women.