Understanding Infertility

Ovulation disorders

One common detectable cause of infertility in women is a hormonal disorder that upsets or even shuts down the normal reproductive cycle.  For example, if the output of reproductive hormones from the pituitary (gonadotropins) or hypothalamus is insufficient or imbalanced, follicles will not develop properly and ovulation will not take place.  This is known as 'anovulatory' infertility.  A common cause of anovulatory infertility is polycystic ovary syndrome (PCOS).

There are some women with rare hypothalamic or pituitary disorders who produce no gonadotropins or GnRH at all and do not experience the follicular development necessary for ovulation.  In either case fertility drugs can induce ovulation and can be given either as tablets or as a series of gonadotropin injections.

Endometriosis

The presence of endometrial tissue (normal uterine lining) in abnormal locations such as the fallopian tubes, ovaries and peritoneal cavity, can be associated with infertility and painful menstruation.  The condition occurs when tissue from the uterine lining (endometrium) is spilled through the fallopian tubes into the pelvis, and implants on the surface of the pelvic cavity and often the ovaries.  This is a common disorder, and may be associated with as many as one-in-four cases of infertility.

Blocked fallopian tubes

In normal conception an egg cell (ovum) in a woman is released from an ovary, travels through a fallopian tube and is fertilized by the man's sperm.  The fertilized egg continues to travel while it undergoes numerous cell divisions, then rests in the uterus to grow.  Blockages in the fallopian tubes prevent sperm from reaching the egg.

Early menopause

Menopause occurs when the number of follicles in the ovaries has fallen to a critically low number and is reflected by a decline in the amount of reproductive hormones released by the ovaries each month.  The most important female reproductive hormone is estrogen and many problems with early menopause occur because of an estrogen deficiency.  Menopause occurs most commonly at the age of 51 years, but the range is quite broad and menopause in the early 40’s is not rare.  Women may have normal ovulatory cycles up to menopause, but in fact, are highly infertile for the six years or so prior to actual cessation of menses.  During this interval of time the miscarriage rate, should pregnancy occur, is quite high.

Uterine Abnormality

The uterus lies just above the cervix and is a hollow muscle that during pregnancy undergoes remarkable growth and development.  During labour it is the uterus that contracts and pushes the baby into the birth canal.  The uterus therefore plays a pivotal role in the ability to carry a pregnancy to term.  Not surprisingly when there are structural abnormalities of the uterus it may affect the ability of a women to carry a pregnancy to term.  Here are a few of the more common abnormalities seen:

• Septate Uterus. A septum divides the uterus into two chambers
• Bicornuate Uterus. A malformation of the uterus where the upper portion is duplicated, creating two distinct uterine areas
• Uterine polyps. Small benign growths in the lining of the uterus that can interfere with implantation of an embryo
• Uterine fibroids. Muscular growths in the wall of the uterus that may push into the uterine cavity and interfere with implantation