Causes in women

Hormonal Infertility

The menstrual cycle is a very complex circuit, controlled and influenced by various hormones. An imbalance in hormone homeostasis can cause deficits in oocyte maturation, lead to lack of ovulation, and cause insufficient corpus luteum formation.

Reasons for hormonal imbalances may include:

• Increased ratio of male hormones
• Stress
• Extreme physical strain (competitive/professional sports)
• Being severely underweight (rapid weight loss, anorexia, bulimia)
• Being severely overweight
• Thyroid issues
• Tumors (rare)

Infertility caused by a defect in the Fallopian Tube

Conception usually takes place inside the fallopian tubes. The fallopian tubes are responsible for directing the fertilized oocyte towards the uterus.

The function of the fallopian tubes may be deficient, or the fallopian tubes may be partially or completely occluded. Causes may include:

• Ascending infection
• Adhesions and scarring of the fallopian tubes after previous operations
• Previous ectopic pregnancies (here it is possible that the fallopian tubes were removed)
• Endometriosis
• Fallopian tube ligature

Endometriosis

15% of women with unwanted childlessness are diagnosed with endometriosis. This means that there is a collection of the endometrium located outside of the uterus, for example, on the ovaries, the fallopian tubes, the intestines, the bladder, or the peritoneum. The exact cause for the development of endometriosis and why it makes natural conception so difficult is still largely unknown.

Polycystic Ovary Syndrome (PCOS)

“Polycystic” means “many cysts”. This term is used to describe the appearance of the ovaries when viewed on ultrasound. The appearance of countless “small cysts” on ultrasound is actually a collection of small follicles that are unable to fully mature due to an increased ration of male hormones. The development of PCOS is thought to be caused due to a disturbance in insulin metabolism.

Immunological causes for infertility

Due to a malfunction of the body’s defense system, sperm or fertilized eggs may be recognized by the immune system as “foreign”, which causes an immune reaction to “fight” off the invader. When this happens, the fertilization of the egg and/or the implantation of the embryo in the uterus becomes nearly impossible. Immunological malfunctions may also be responsible for repeated miscarriages.

Changes to the cervix and uterus

Closure and scarring after inflammation or surgery can make it more difficult for sperm to pass through the cervix or the uterus to reach the fallopian tubes. In very rare cases, congenital malformations of the cervix or uterus may cause unwanted childlessness.

Age

Women are born with a limited number of egg cells, reaching up to a total of 400,000 at birth. With increasing age, the number of active and resting follicles, as well as the hormones that encourage their growth, decreases. As a result, oocytes begin to fail to mature properly, increasing the total number of menstrual cycles that occur without successful ovulation.

The “aging of the oocytes” is also an important factor. Aging leads to an increase in chromosomal changes, which can prevent the fertilization of the oocyte, prevent implantation of the embryo in the uterus, or may lead to miscarriages.