Infertility Health Article

Definition

Infertility is the failure of a couple to conceive a pregnancy after trying to do so for at least one full year. In primary infertility, pregnancy has never occurred. In secondary infertility, one or both members of the couple have previously conceived, but are unable to conceive again after a full year of trying.

Description

Approximately 20% of couples struggle with infertility at any given time. Infertility has increased as a problem over the last 30 years. Some studies blame this increase on social phenomena, including the tendency for marriage and starting a family to occur at a later age. For women, fertility decreases with increasing age:

• Infertility in married women ages 16–20 = 4.5%.
• Infertility in married women ages 35–40 = 31.8%.
• Infertility in married women over the age of 40 = 70%.

Presently, individuals often have several sexual partners before they marry and try to have children. This increase in numbers of sexual partners has led to an increase in sexually transmitted diseases. Scarring from these infections, especially from pelvic inflammatory disease (infection of the female reproductive organs) seems to be in part responsible for the rise in infertility. Furthermore, use of some forms of the contraceptive called the intrauterine device (IUD) has contributed to an increased rate of pelvic inflammatory disease, with subsequent scarring. A study in 2001 found that copper IUDs have probably been wrongfully blamed for tubal infertility, while infection from the sexually transmitted disease chlamydia was likely the cause.

To understand the causes of infertility, it is first necessary to understand the basics of human reproduction. Fertilization occurs when a sperm from the male merges with an egg (ovum) from the female, creating a zygote that contains genetic material (DNA) from both the father and the mother. If pregnancy is then established, the zygote will develop into an embryo, then a fetus, and ultimately, if all goes well, a baby will be born.

Sperm are small cells that carry the father's genetic material. The sperm are mixed into a fluid called semen, which is discharged from the penis during sexual intercourse. The whiplike tail of the sperm allows the sperm to swim up the female reproductive tract, in search of an egg.

The ovum is the cell that carries the mother's genetic material. Once a month, a single mature ovum is produced, and leaves the ovary in a process called ovulation. This ovum enters a tube leading to the uterus (the fallopian tube) where fertilization occurs.

When fertilization occurs, the resulting cell (which now contains genetic material from both the mother and the father) is called the zygote. This single cell will divide into multiple cells and the resulting cluster of cells (called a blastocyst) moves into the womb (uterus). The uterine lining (endometrium) has been preparing itself to receive a pregnancy by growing thicker. If the blastocyst successfully attaches itself to the wall of the uterus, then pregnancy has been achieved.