Chapter 32 Infertility: General Considerations
THE CHALLENGE
To assist couples who experience difficulty conceiving through normal means.
Scope of the Problem: The inability to conceive and bear children affects 8% to 18% of the American population. Under ordinary circumstances, 80% to 90% of normal couples conceive during 1 year of attempting pregnancy. Infertility is generally defined as failure to conceive after 1 year of regular, unprotected intercourse. Infertility may be further subdivided into primary and secondary types based on the patient’s past reproductive history; patients with infertility who are nulligravid are in the primary infertility group; those who have achieved a pregnancy more than 1 year previously, regardless of the outcome of that pregnancy, are grouped in the secondary infertility group. Slightly more than one half of infertility patients fall into the primary group.
Objectives of Management: To establish the relevant cause or causes and develop strategies that result in conception and delivery. With improved understanding of the physiology of conception and a wide range of technologies that may be brought to bear to assist with procreation, 85% of “infertile” couples may be helped.
TACTICS
Relevant Pathophysiology: The male partner brings to the union sperm-laden semen, which is deposited in the vagina during intercourse. The average ejaculate has a volume of between 1 and 15 mL and contains more than 20 million spermatozoa. The survival of sperm in the female genital tract is thought to be at least 96 hours and may be as long as 8 days. However, it is probable that sperm are capable of fertilizing an egg for only the first 24 to 48 hours after ejaculation. The woman’s gametic contribution, the oocyte, is released from the ovary during the mid-cycle process of ovulation, 14 days before the onset of menstruation, regardless of the total cycle length. Progesterone is produced by the luteinized follicle, producing a characteristic increase of between 0.5°F and 1°F in basal body temperature. The oocyte may be fertilized during the first 24 hours after ovulation only. Generally, fertilization takes place in the distal portion of the fallopian tube. Pregnancy does not result unless the zygote passes into the uterine cavity at the correct time (3 to 5 days after fertilization), encounters a receptive endometrium, and can successfully implant and grow.
Strategies: To achieve pregnancy, three critical elements must be in place: (1) a sperm must be available, (2) an egg must be available, and (3) the sperm and egg must meet at a time and place conducive to fertilization. It is the investigation of these three elements that constitutes the evaluation of the infertile couple.
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