The exact incidence of the various factors causing infertility varies among different populations. In general, however, the following incidences have been reported.

• Ovulatory disorders: 15–25%
  
• Endometriosis: 5–10%
  
• Pelvic adhesions: 10%
  
• Tubal blockage: 10–15%
  
• Female factor (alone): 40–50%
  
• Male factor (alone): 20%
  
• Combination female + male: 30–40%
  
• Unexplained: 10–25%

It has not been demonstrated with certainty that other abnormalities, such as antisperm antibodies, luteal-phase deficiency, subclinical genital infection or subclinical endocrine abnormalities such as hypothyroidism or hyperprolactinemia in ovulatory women, are a true cause of infertility. No prospective randomized studies have demonstrated that directed treatment of these latter entities results in greater fecundability than that which occurs without treatment. Therefore, couples with these abnormalities are treated in a manner identical to that of the 10–15% of couples in whom a specific cause is not found and who are considered to have idiopathic or unexplained infertility.

At the time of the initial consultation for infertility, the clinician should take a complete history and perform a physical examination. In addition, a discussion about the normal reproductive process, normal fecundability, and the optimal time of intercourse should be undertaken. While reviewing the diagnostic evaluation, the clinician should discuss not only the type of tests but also their sequence and relation to the timing in the menstrual cycle as well as the discomfort and costs of the various diagnostic procedures.

The available therapies and the prognosis for treatment of the various causes of infertility can also be included in the dialogue. Methods to increase the fecundability rates of couples with normal diagnostic findings, such as controlled ovarian hyperstimulation and intrauterine insemination (IUI), as well as assisted reproductive technologies (ART), should be discussed.

Each couple should be instructed about the optimal time in the cycle for conception to occur. A study was performed in which fertile couples who stopped contraception in order to conceive recorded the cycle day when they had a single act of sexual intercourse. Hormone analyses were performed to determine the day of ovulation. All the couples who had intercourse after ovulation occurred did not become pregnant. The pregnancy rate was about 30% if intercourse occurred on the day of ovulation as well as 1 and 2 days before ovulation occurred. The pregnancy rate was about 10% if coitus occurred 3, 4 or 5 days before ovulation. No pregnancies occurred when intercourse took place 6 days or more days before ovulation.

Therefore, the optimal time for sexual intercourse is 1 or 2 days prior to or on the day of ovulation. Sperm retain their viability and fertilizing capacity for a longer period than the ovum is capable of being fertilized after ovulation occurs. Therefore it seems reasonable to advise couples to have sperm in the female reproductive tract awaiting the release of the egg, and to err on the early side when timing intercourse.

Ovulation typically takes place 14 days prior to the onset of the next menstrual cycle. Therefore, couples who want to use the “calendar method” for timing intercourse should consider the shortest and the longest menstrual interval of the female partner, and then time intercourse for 14 days prior to the anticipated time of the next menstruation. For example, if the shortest cycle is 24 days and the longest cycle is 32 days, then the couple should have intercourse every other day between cycle days 10 and 18.

Measurement of LH by commercially available urinary LH detection tests is the best way to detect ovulation and thus to determine the optimal time to have intercourse or insemination. Ovulation occurs in most cases 12–24 hours following detection of the LH surge in the urine. Testing should be performed between 10 am and 8 pm, excluding the first morning urine, as the LH surge often begins in the early morning hours and is not detectable in the urine until several hours later.

Initial evaluation