Small relative risks (a twofold or lesser increase in disease frequency) become scientifically acceptable with (a) repeated consistent findings from studies that (b) address the most important forms ...of bias and confounding, and (c) when there is a plausible biologic mechanism. The third-generation oral contraceptive controversy is an example of such a relevant but small relative risk and demonstrates the problem of interpretation and implementation into medical practice guidelines.
To determine how a standard infertility investigation is conducted and to determine the use of fertility tests used in such investigations in relation to WHO guidelines.
Questionnaire survey.
Dutch ...medical schools.
A questionnaire survey among the heads of all 8 university and 20 non-university teaching departments of obstetrics and gynaecology or their fertility units was conducted. One non-university department failed to respond.
The examinations recommended by the WHO (general physical examination, andrological and gynaecological examination, semen analysis, ovulation detection, tubal patency testing) in general were carried out, but general physical examination of the male as a rule was only carried out if indicated. Popular routine examinations not recommended by the WHO were the postcoital test and hysterosalpingography. Regarding the postcoital test, there was variation in the time interval after coitus and the standards for spermatozoal motility.
Standard fertility investigations are usually based on empiricism and tradition, including the testing recommended by the WHO.
