Infertility is defined as the inability to conceive after 1 year of unprotected intercourse of reasonable frequency. It can be subdivided into primary infertility, that is, no prior pregnancies, and secondary infertility, referring to infertility following at least one prior conception.
Conversely, fecundability is the ability to conceive, and data from large population studies show that a monthly probability of conceiving is 20 to 25 percent. In those attempting conception, approximately 50 percent of women will be pregnant at 3 months, 75 percent will be pregnant at 6 months, and more than 85 percent will be pregnant by 1 year (Fig. 19-1) (Guttmacher, 1956; Mosher, 1991).
Time required for conception.
Infertility is a common condition, affecting 10 to 15 percent of reproductive-aged couples. Of note, even without treatment, approximately half of women will conceive in the second year of attempting. Although the prevalence of infertility is believed to have remained relatively stable during the past 40 years, the demand for infertility evaluation and treatment has increased (Chandra, 2010). With the well-publicized advances in infertility treatment, patients now have greater hope that medical intervention will help them achieve their goal.
Most couples are more correctly considered to be subfertile, rather than infertile, as they will ultimately conceive if given enough time. This concept of subfertility can be reassuring to couples. However, there are obvious exceptions, such as the woman with bilaterally obstructed fallopian tubes or the azoospermic male.
It is generally agreed that an infertility evaluation should be considered in any couple that has failed to conceive in 1 year. There are a number of clinical scenarios, however, in which evaluation should be considered sooner. For example, to delay evaluation in an anovulatory woman or a woman with a history of severe pelvic inflammatory disease (PID) may not be appropriate. Furthermore, fecundability is highly age related, thus evaluation at 6 months should be performed in women older than 40 years who desire conception, and according to some experts, in women older than 35. As a part of infertility evaluation, the patient should be prepared for an anticipated pregnancy. A comprehensive list of preconceptional topics is found in Table 1-3.
Successful pregnancy requires a complex sequence of events including ovulation, ovum pick-up by a fallopian tube, fertilization, transport of a fertilized ovum into the uterus, and implantation into a receptive uterine cavity. With male infertility, sperm of adequate number and quality must be deposited at the cervix near the time of ovulation. Remembering these critical events can help direct a clinician to develop an appropriate evaluation and treatment strategy.
In general, infertility can be attributed to the female partner one third of the time, the male partner one third of the time, and ...