Infertility

Infertility is a couple's inability to conceive a child after attempting to do so for at least one full year. Primary infertility refers to a situation in which pregnancy has never been achieved. Secondary infertility refers to a situation in which one or both members of the couple have previously conceived a child, but are unable to conceive again after a full year of trying.

Currently, in the United States, about 20% of couples struggle with infertility at any given time. Infertility has increased as a problem, as demonstrated by a study comparing fertility rates in married women ages 20-24 between the years of 1965 and 1982. In that time period, infertility increased 177%. Some studies attribute this increase on primarily social phenomena, including the tendency for marriage to occur at a later age, and the associated tendency for attempts at first pregnancy to occur at a later age. Fertility in women decreases with increasing age, as illustrated by the following statistics:

• infertility in married women ages 16-20: 4.5%
• infertility in married women ages 35-40: 31.8%
• infertility in married women over age 40: 70%.

Since the 1960s, there has also been greater social acceptance of sexual intercourse outside of marriage, and individuals often have multiple sexual partners before they marry and attempt conception. This has led to an increase in sexually transmitted infections. Scarring from these infections, especially from pelvic inflammatory disease (PID)—a serious infection of the female reproductive organs—seems to be partly responsible for the increase. Furthermore, use of the contraceptive device called the intrauterine device (IUD) also has contributed to an increased rate of PID, with subsequent scarring.

To understand issues of infertility, it is first necessary to understand the basics of human reproduction. Fertilization occurs when a male sperm merges with a female ovum (egg), creating a zygote, which 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 a baby will be born.

Sperm are small cells that carry the father's genetic material. This genetic material is contained within the oval head of the sperm. Sperm are produced within the testicles, and proceed through a number of developmental stages in order to mature. This whole process of sperm production is called spermatogenesis. The sperm are mixed into a fluid called semen, which is discharged from the penis during a process called ejaculation. The whip-like tail of the sperm allows the sperm motility; that is, permits the sperm to essentially swim up the female reproductive tract, in search of the egg it will attempt to fertilize.

The ovum (or egg) is the cell that carries the mother's genetic material. These ova develop within the ovaries. Once a month, a single mature ovum is produced and leaves the ovary in a process called ovulation. This ovum enters the fallopian tube (a tube extending from the ovary to the uterus) where fertilization occurs.

If fertilization occurs, a zygote containing genetic material from both the mother and father results. This single cell will divide into multiple cells within the fallopian tube, and the resulting cluster of cells (called a blastocyst) will then move into the uterus. The uterine lining (endometrium) has been preparing itself to receive a pregnancy by growing thicker. If the blastocyst successfully reaches the inside of the uterus and attaches itself to the wall of the uterus, then implantation and pregnancy have been achieved.

Unlike most medical problems, infertility is an issue requiring the careful evaluation of two separate individuals, as well as an evaluation of their interactions with each other. In about 3-4% of couples, no cause for their infertility will be discovered. The main factors involved in causing infertility, listing from the most to the least common, include: (1) Male factors; (2) Peritoneal factors; (3) Uterine/tubal factors; (4) Ovulatory factors; and (5) Cervical factors.